Figure below shows two paths that may be taken by a gas to go from a state A to a state C : In process AB, 400 J of heat is added to the system and in process BC, 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be :
In a thermodynamic process helium gas obeys the law T p 2 5 = constant .The heat given to the gas when temperature of m moles of gas is raised from T to 2T is:
A gas is suddenly expanded such that its final volume becomes 3 times its initial volume. If the specific heat at constant volume of the gas is 2R, then the ratio of initial to final pressure is nearly equal to:
A refrigerator works between 4 o C and 30 o C. It is required to remove 600 calories of heat every second in order to keep the temperature of the refrigerated space constant. The power required is : (Take 1 cal : 4.2 joules)
An ideal heat engine exhausting heat at 27°C is to have 25% efficiency. It must take heat at:
An inventor claims to have made an engine which consumes 1 g fuel per sec (of calorific value 2 kcal /g) and delivers 10 kW of power. Mark the correct statement:
An engine is supposed to operate between two reservoirs at temperature 727 ∘ C and 227 ∘ C . The maximum possible efficiency of such an engine is :
100 mol of an ideal gas is heated from 10° to 20°C keeping its (i) volume constant (ii) pressure constant. Let Δ U a and Δ U b denote the change in the internal energy of the gas due to process (i) and (ii), respectively. Then, which of the following shall be true?
One mole of an ideal gas is heated at a constant pressure of 1 atm from 0 0 C to 100 0 C. Work done by the gas is
1 g of water, of volume 1 cm 3 at 100°C, is converted into steam at same temperature under normal atmospheric pressure ( 1 × 10 5 Pa ) . The volume of steam formed equals 1671 cm 3 . If the specific latent heat of vaporisation of water is 2256 J/g, the change in internal energy is,
The efficiency of a carnot engine is 50% and temperature of sink is 500 K. If temperature of source is kept constant and its efficiency raised to 60%, then the required temperature of sink will be?
Calculate the coefficient of performance of a refrigerator working between -10 o c to 20 o c is
Two moles of an ideal monoatomic gas undergoes a process 1 – 2 – 3 as shown in figure. Then total heat supplied to the gas in the process is
The temperature of sink of Camot-engine is 27 0 C . Efficiency of engine is 25%. Then temperature of source is
An engine is supposed to operate between two reservoirs at temperature 727 0 C and 227 0 C . The maximum possible efficiency of such an engine is
The efficiency of a Carnot heat engine
Two Camot engines A and B are operated in succession. The first one, ,A receives heat from a source at T 1 = 800 K and rejects to sink at T 2 K. The second engine B receives heat rejected by the first engine and rejects to another sink at T 3 = 300 K. If the work outputs of two engines are equal, then the value of T 2 is
The rise in temperature when an ideal monoatomic gas at 27°C is compressed adiabatically to (8/27) of its original volume is:
In an adiabatic expansion of air the volume increases by 5%. What is the percentage change in pressure?
A Carnot engine whose sink is at 300 K has an efficiency of 40%. By how much should the temperature of source be increased so as to increase its efficiency by 50% of original efficiency?
An ideal refrigerator has a freezer at a temperature of -13 °C. The coefficient of performance of the engine is 5.The temperature of the air (to which heat is rejected) will be :
A Carnot engine operates with source at 127 °C and sink at 27 °C. If the source supplies 40 k J of heat energy, the work done by the engine is :
Figure shows the P-V diagram for a fixed mass of an ideal gas undergoing cyclic process ABCA. AB represents isothermal process. Which of the graphs shown in figure represents the P-T diagram of the cyclic process?
The first law of thermodynamics incorporates the concepts of (a) equivalence of heat and work (b) conservation of heat (c) conservation of energy
The efficiency of a Carnot engine kept at the temperatures of 27 0 C and 127 0 C is
The water of volume 4 m 3 at the height 20 m is pressed by 2 X 10 5 N pressure. The work done by motor is
The efficiency of a Carnot engine is 60%. If the temperature of source is 127 0 C. The sink must be maintained at
A gas is taken through the cycle A B C A , as shown. What is the net work done by the gas?
The P-V diagram for an ideal gas in a piston cylinder assembly undergoing a thermodynamic process is shown in the figure. The process is
Hail stone at 0 ∘ c falls from a height of 1 Km on an insulating surface converted whole of its kinetic energy into heat. What part of it will melt? (g=10m/s 2 )
A closed container contains 2 moles of H 2 . If one mole of H 2 is dissociated into atomic hydrogen, then molar specific heat of the mixture at constant volume is
An ideal gas is allowed to expand freely against vacuum in a rigid insulated container. The gas undergoes
Which of the following is an equivalent cycle process corresponding to the thermodynamic cyclic process given in the figure , where, 1 2 is adiabatic ( Graphs are schematic and are not to scale)
A sink, that is a system where heat is rejected, is essential for the conversion of heat into work. From which law the above inference follows?
In a Carnot engine, when T 2 = 0 0 C and T 1 = 200 0 C its efficiency is η 1 and when T 1 = 0 0 C and T 2 = – 200 0 C . Its efficiency is η 2 , and then what is η 1 η 2 ?
A Carnot engine has the same efficiency between 800 K to 500 K and x K to 600 K. The value of x is
A freezer has coefficient of performance equal to 5. When 3.6 × 10 6 J work is done on the freezer, what mass of water at 0 0 C is converted into ice cubes at 0 0 C.
A carnot engine is made to work first between 200k and 100k and then between 400k and 200k. The ratio of efficiencies η 2 / η 1 in two cases is
First law of thermodynamics represents.conservation of:
Which of the following is incorrect regarding the first law of thermodynamics?
If a system undergoes contraction of volume, then the work done by the system is:
When 110 J of heat is added to a gaseous system, internal energy increases by 40 J, the amount of work done is:
4 mole of a diatomic ideal gas are heated at constant pressure from 27°C to 327°C. Internal energy of the gas increases by: (take R = 2 cal/mol-K)
A certain quantity of heat energy is given to a diatomic ideal gas which expands at constant pressure. The fraction of the heat energy that is converted into work is:
4 moles of a diatomic gas is heated at constant pressure to increase the temperature from 27 0 c to 327 0 c the heat supplied to the gas is:
Which of the following statements is correct for any thermodynamic system?
A gas is taken through the cycle A ➔ B ➔ C ➔ A, as shown, what is the net work done by the gas?
In an adiabatic change:
Initial pressure and volume of a gas are P and V respectively.First its volume is expanded to 4Vby isothermal process and then again its volume makes to be V by adiabatic process, then its final pressure is ( γ = 1.5):
A given mass of a gas is compressed isothermally until its pressure is doubled. It is then allowed to expand adiabatically until its original volume is restored and its pressure is then found to be 0.75 of its initial pressure. The ratio of the specific heats of the gas is approximately:
One mole of an ideal gas goes from an initial state A to final state B via two processes. It first undergoes isothermal expansion from volume V to 3 V and then its volume is reduced from 3V to V at constant pressure. The correct P-V diagram representing the two processes is :
Carnot engine takes in 3000 k cal of heat from a reservoir at 627°C and gives it to a sink at 27°C. The work done by the engine is:
A scientist says that the efficiency of his heat engine which work at source temperature 127 o C and sink temperature 27 o C is 26%, then :
A refrigerator transfer 180 joule of energy in one second from temperature – 3 o C to 27 o C. Calculate the average power consumed, assuming no energy losses in the process.
The temperature entropy diagram of a reversible engine . cycle is given in the Fig. Its efficiency is:
1 mole of a monoatomic gas at temperature T 0 expand slowly according to the law P 2 is proportional to T . Its final temperature is 2 T 0 , then heat supplied to the gas is
One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure The change in internal energy of the gas during the transition is
A gas is taken through the cycle A B C A, as shown. What is the net work done by the gas?
A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then
A thermodynamic system undergoes cyclic process ABCDA as shown in figure. The work done by the system in the cycle is
P-V curve of a diatomic gas is shown in the figure. Find the total heat given to the gas in the process A B C
Heat flows from a reservoir at 373 K to a reservoir at 273k through a copper rod as shown in the figure. The heat then leaves the 273K reservoir and enters a Carnot engine, which uses part of this heat to do work and rejects the remainder to a third reservoir at 173K.What fraction of the heat leaving the 373K reservoir is rendered unavailable for doing work, as compared to the situation where a Carnot engine is connected directly between the 373K and 173K reservoirs?
A gas has molar heat capacity C = 24.9 J / mol K in the process P 2 T = Constant . Then ( R = 8.3 J / mol K )
Out of the following which quantity does not depend on path
Work done on or by a gas, in general depends upon the
When the amount of work done is 333 cal and change in internal energy is 167 cal, then the heat supplied is
In an isothermal change, an ideal gas obeys
Pressure-temperature relationship for an ideal gas undergoing adiabatic change is ( γ = C p / C v )
Correct statement among the following is
In a given process on an ideal gas, dW = 0 and dQ < 0. Then for the gas :
A cycle tyre bursts suddenly. What is the type of this process
A refrigerator absorbs 2000 cals of heat from ice trays. If the coefficient of performance is 4, then work done by the motor is
A gas for which γ = 1.5 is suddenly compressed to the 1 4 th of the initial volume. Then the ratio of the final to the initial pressure is
A monoatomic ideal gas, initially at temperature T 1 , is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature T 2 by releasing the piston suddenly. If L 1 and L 2 are lengths of the gas column before and after expansion respectively, then T 1 / T 2 is given by
Starting with the same initial conditions, an ideal gas expands from volume V 1 to V 2 in three different ways. The work done by the gas is W 1 , if the process is isothermal W 2 , if isobaric and W 3 , if adiabatic, then
The equation of a state of a gas is given by ρ ( V – b ) = nRT . 1 mol of a gas is isothermally expanded from volume V to 2 V , the work done during the process is
Unit mass of a liquid with volume V 1 is completely changed into a gas of volume V 2 at a constant external pressure ρ at temperature T . If the latent heat of evaporation is L , then the increase in the internal energy of the system is
A Carnot engine working between 300 K and 600 K has work output of 800 J cycle -1 . The amount of heat energy supplied from the source of engine in each cycle is
Two cylinders A and B fitted with pistons contain equal amounts of an ideal diatomic gas at 300 K. Piston A is free to move and piston of B is fixed. Same amount of heat is given to the gases in the two cylinders. Temperature of the gas in cylinder A increases by 30 K, then increase in temperature of the gas in the cylinder B is ( γ = 14 for diatomic gas) [EAMCET 2013]
A perfect gas goes from state A to state B by absorbing 8 X 10 5 J of heat and doing 6.5 x 10 5 J of external work. It is now transferred between the same two states in another process in which it absorbs 10 5 J of heat. In the second process
The rise in temperature when an ideal monoatomic gas at 27°C is compressed adiabatically to (8/27) of its original volume is:
4 gm of He at 27°C is mixed with 16 gm of O 2 at 37°C. If both gases are considered as ideal gases, temperature of the mixture will be nearly:
Two rigid boxes containing different ideal gases are placed on a table. Box A contains one mole of nitrogen at temperature T o , while Box B contains one mole of helium at temperature (7/3) T 0 . The boxes are then put into thermal contact with each other and heat flows between them until the gases reach a common final temperature (ignore the heat capacity of boxes). Then, the final temperature of the gases T 1 , in terms of T 0 is
A diatomic gas, having C P = 7 2 R and C v = 5 2 R is heated at constant pressure. The ratio dU : dQ : dW
In the given (V – T) diagram, what is the relation between pressures P 1 a n d P 2 ?
A Carnot engine, having an efficiency of η = 1 10 as heat engine, is used as a refrigerator. If the work done on the system is 10J, the amount of energy absorbed from the reservoir at lower temperature is
Two Carnot engines A and B are operated in series. The engine A receives heat from the source at temperature T 1 and rejects the heat to the sink at temperature T. The second engine B receives the heat at temperature T and rejects to its sink at temperature T 2 . For what value of T the efficiencies of the two engines are equal
A carnot engine having an efficiency of 1 10 as heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absorbed from the reservoir at lower temperature is
One mole of a gas obeying the equation of state P(V – b) =RT is made to expand from a state with coordinates ( P 1 , V 1 ) to a state with ( P 2 , V 2 ) along a process that is depicted by a straight line on a P – V diagram. Then, the work done is given by :
140 calories of heat is required to raise the temperature of 2 moles of an ideal diatomic gas at constant pressure from 0° C to 10°C. How much heat is required to heat it through same range at constant volume?
For a certain gas the ratio of specific heat is 1.5, for this has:
The value of γ for helium is 5/3. Calculate the specific heat capacity at constant volume, if it’s molar mass is 4:
The value of specific heat at constant volume is 0.723 kJ/kgK, if the density of gas at 27°C and 10 5 Nm -2 is 1.2 kg m − 3 , what is the specific heat at constant pressure?
One mole of mono atomic gas is mixed with three moles of diatomic gas. What is molecular specific heat of the mixture at constant volume?R=8.31 J/mole/K
A monoatomic gas is expanded adiabatically to n times its initial volume. The ratio of final rate of collision of molecules with unit area of container walls to the initial rate will be
The coefficient of performance, in a mechanical refrigerator, the lower temperature coils of the evaporator are at − 23 0 C and compressed gas in the condenser has a temperature of 77 0 C , is
Two liquids at temperature 60° C and 20° C respectively have masses in the ratio 3:4 and the specific heats in the ratio 4:5, if they are mixed the resultant temperature is:
If one mole of a mono atomic gas γ= 5 3 , is mixed with one mole of diatomic gas γ= 7 5 , what is the value of γ for the mixture.
What amount of heat is needed to raise the temperature of 2 × 10 – 2 k g of nitrogen at room temperature to raise it’s temperature by 45° C at constant pressure?(given molecular mass=28 and R=8.3 J m o l – 1 K – 1 ; C p =7R/2 )
The ratio of the slopes of P-V graphs of adiabatic and isothermal process is(in terms of specific heat ratio γ )
In an adiabatic change, the pressure and temperature of a mono atomic gas are related as PαT C , where c equals
In a thermodynamic process the pressure of a fixed mass of a gas is changed in such a manner that the gas molecules give out 30 J of heat and 10 J of work done on the gas. If the initial internal energy of the gas was 40 J. Then the final internal energy will be ?
An ideal mono atomic gas is taken round a cycle ABCDA as shown in figure, work done during the cycle is
A carnot engine working between 300 K and 600 K has a work output of 800 J per cycle, the amount of heat energy supplied to the engine from the source in each cycle is
One mole of mono atomic gas γ = 5 3 is mixed with one mole of diatomic gas γ = 7 5 . What will be the value of γ for the mixture.
A gas for which δ = 4 3 , is heated at constant pressure, what percentage of total heat is supplied for doing external work?
A carnot engine whose source is at 400 K takes 200 cal of heat and rejects 150 cal to sink. What is the temperature of sink?
A Carnot’s engine, with its cold body at 17 0 C has 50% efficiency. If the temperature of its hot body is now increased by 145 0 C , the efficiency becomes
The ratio of specific heats of a gas is x. The change in internal energy of one mole of the gas, when the volume changes from V to 3V at constant pressure P is
A monoatomic ideal gas is supplied the heat Q very slowly keeping the pressure constant. Then work done by the gas will be
A carnot engine whose sink is at 300K has an efficiency of 40%. By how much should the temperature of the source be increased, so as to increase the efficiency by 50% of original efficiency?
A Carnot engine having an efficiency of 1 10 is being used as a refrigerator. If the work done on the refrigerator is 10J, the amount of heat absorbed from the reservoir at lower temperature is :
An ideal heat engine working between temperatures T 1 and T 2 ( T 1 > T 2 ) has efficiency η . If both temperatures are lowered by 100K each, The new efficiency of the engine will be
In adiabatic process R = 2 3 C V . The pressure of the gas will be proportional to
For the process shown in volume-temperature (V – T ) diagram the pressure from a to b
A closed container contains 2 moles of hydrogen gas. If 50% of hydrogen molecules are dissociated into atomic hydrogen, the molar specific at constant volume of the mixture will be
An engine takes in 5 moles of air at 20ºC and 1atm, and compresses it adiabatically to 1/10th of the original volume. Assuming air to be a diatomic ideal gas made up of rigid molecules, the change in its internal energy during this process comes out to be X kJ. The value of X to the nearest integer is
One mole of a monoatomic gas is mixed with one mole of a diatomic gas. What will be the γ for the mixture ?
An ideal heat engine exhausting heat at 77°C is to have a 30% efficiency. It must take heat at
A gas is compressed at a constant pressure of 50 N/m 2 from a volume 10m 3 to a volume of 4m 3 . 100J of heat is added to the gas then its internal energy
A heat engine has an efficiency . Temperatures of source and sink are each decreased by 100K. Then, the efficiency of the engine
Five moles of hydrogen is heated through 20K under constant pressure. If R=8.312J/mole K find the external work done.
The amount of heat must be supplied to 2.0×10 –2 kg of nitrogen (at room temperature) to raise its temperature by 45 o C at constant pressure is (Molecular mass of N 2 = 28; R = 8.3J mol –1 K –1 )
An ideal monatomic gas is taken from state A to B, then from state B to state C and finally back to state A as shown in the p-V diagram. Which of the following is correct for BC process?
A mass m of an ideal gas initially has volume Voand temperature To. When it is kept at constant volume Vo, heat Q is required to increase its temperature to To + DT. If the volume is not kept constant, but the gas expands from Vo to 3Vo when the temperature increases from To to (To + 2DT), then the heat supplied must be
Diatomic gas at pressure ‘P’ and volume ‘V’ is compressed adiabatically to 1/32 times the orginal volume. Then the final pressure is
P–V diagram of an ideal gas is shown in the figure. Work done by the gas in the process ABCD is
A monoatomic ideal gas, initially at temperature T 1 , is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature. T 2 by releasing the piston suddenly. IF L 1 and L 2 are teh lengths of the gas column before and after expansion respectively, then T 1 / T 2 is given by
Heat is supplied to a diatomic gas at constant pressure. The ratio of ΔQ : ΔU : ΔW is:
A cyclic process ABCD is shown in the p-V diagram. Which of the following curves represent the same process?
An ideal gas takes part in two thermodynamic processes ab and ac in which it is heated from the same initial state. The points b and c happen to be on an isotherm. In which process more heat is absorbed?
A Carnot engine, having an efficiency of η = 1/10 as heat engine, is used as a refrigerator. If the work done on the system is 10J, the amount of energy absorbed from the reservoir at lower temperature is
Engine A receives three times more input heat, produces five times more work, and rejects two times more heat than engine B. The efficiency of engine A is
Suppose 0.5 mole of an ideal gas undergoes an isothermal expansion as energy is added to it as heat Q. Graph shows the final volume V f versus Q. The temperature of the gas is ( use In 9 = 2 and R= )
An ideal gas undergoes cyclic process ABCDA as shown in given P-V diagram. The amount of work done by the gas in a cycle is,
Statement I : When a bottle of cold carbonated drink is opened, a slight fog forms around the opening. Statement II : Adiabatic expansion of the gas causes lowering of temperature and condensation of water vapours.
The volume of a gas is reduced adiabatically to ( 1 4 ) of its volume at 27 0 C . If γ = 1.4, the new temperature will be
An ideal gas ( γ = 1.5) is expanded adiabatically. How many times has the gas to be expanded to reduce the root mean square velocity of molecules 2.0 times?
A Carnot engine operates between 327 0 C and 27 0 C . How much heat (in joules) does it take from the 327 0 C reservoir for every 100 J of work done?
The temperature inside a refrigerator is t 2 0 C and the room temperature is t 1 0 C . The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be
A refrigerator works between 4 0 C and 30 0 C . It is required to remove 600 calories of heat every second in order to keep the temperature of the refrigerated space constant. The power required is
The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is – 20 o C , the temperature of the surroundings to which it rejects heat is:
A scientist says that the efficiency of his heat engine which operates at source temperature 127 0 C and sink temperature 27 o C is 26%,then
A Carnot engine used first an ideal monoatomic gas ( γ = 5 3 ) and then an ideal diatomic gas ( γ = 7 5 ) as its working substance. The source and sink temperatures are 411 0 C and 69 0 C respectively and the engine extracts 1000 J of heat from the source in each cycle. Then
A Carnot’s engine operates with an efficiency of40% with its sink at 27 0 C . By what amount should the temperature of the source be increased with an aim to increase the efficiency by 10%?
A heat engine receives 50 kcal of heat from the source per cycle, and operates with an efficiency of 20%. The heat rejected by engine to the sink per cycle is
In a mechanical refrigerator, the low temperature coils are at a temperature of – 23 0 C and the compressed gas in the condenser has a temperature of 27 0 C . The theoretical coefficient of performance is
A Carnot engine working between 300 K and 600 K has work output of 800 J per cycle. What is amount of heat energy supplied to the engine from source per cycle?
An ideal gas heat engine operates in a Carnot’s cycle between 227 0 C and 127 0 C . It absorbs 6 x lO 4 J at high temperature. The amount of heat converted into work is ….
A tyre pumped to a pressure 3.375 atm at 27 0 C suddenly bursts. What is the final temperature ( γ = 1.5)?
During adiabatic process pressure P versus density ρ equation is:
Find the work done by an ideal gas during a closed cycle 1 – 4 – 3 – 2 – 1 as shown if P 1 = 10 5 Pa, P 0 = 3 × 10 5 Pa, P 2 = 4 × 10 5 Pa, V 2 – V 1 = 100 litre and segments 4 – 3 and 2 – 1 of the cycle are parallel to the V – axis.
An ideal gas undergoes a circular cycle as shown in the figure. Find the ratio of maximum temperature of cycle to minimum temperature of cycle:
The maximum attainable temperature of an ideal gas in the process P = P o − α V 2 (Where P o and α are positive constants, n is a number of moles and R is universal gas constant) is
Pick out the incorrect statement among the following
In a given process on an ideal gas, dW = 0 and dQ < 0. Then for the gas
If Pis the pressure, U the internal energy and dV the volume increase of a system, then by definition:
Which of the following parameters does not characterise the thermodynamic state of matter?
An ideal gas is taken through a cyclic thermodynamical process through four steps. Amounts of heat involved in these steps are : Q 1 = 5960 J, Q 2 = -5585 J, Q 3 = -2980 J and Q 4 = 3645 J respectively. The corresponding works involved are : W 1 = 2200 J, W 2 = – 825 J, W 3 = -1100 J and W 4 respectively. Value of W 4 is:
When a system is taken from state i to state/along the path iaf, it is found that Q = 50 cal and W = 20 cal. Along the path ibf, Q = 36 cal. W along the path ibf is:
When volume changes from V to 2V at constant pressure P, then the change in internal energy will be :
The volume of a gas changes from 2 litre to 10 litre at constant temperature 300 K: The change in internal energy will be:
During the melting of a slab of ice at 273 K at atmospheric pressure: (i) positive work is done by the ice-water system on the atmosphere (ii) positive work is done on the ice-water system by the atmosphere (iii) the internal energy of the ice-water system increases (iv) the internal energy of the ice-water system decreases
One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure. The change in internal energy of the gas during the transition is :
A thermodynamic system undergoes cyclic process ABCDA as shown in Fig.The work done by the system in the cycle is:
In a container, a gas at NTP is slowly compressed to one fourth of its volume, its final pressure is P. In another container, a gas at NTP is suddenly compressed to one fourth of its volume, its final pressure is P’, then: (take γ = 3/2)
A monoatomic gas ( γ = 5 3 ) ·is suddenly compressed to (1/8) its volume adiabatically; then the pressure of the gas will change to:
1 g of an ideal gas expands isothermally; heat flow will be:
The pressure and density of a diatomic gas γ = 7 / 5 change adiabatically from P , ρ to P ‘ , ρ ‘ . If P ‘ / P = 32 , ρ ‘ / ρ should equal:
An ideal gas is found to obey the relation PV 3 2 = constant during an adiabatic process. If such a gas initially at a temperature T is compressed to half of initial volume, then its final temperature will be
For an adiabatic expansion of a perfect gas the value of ∆ P / P is equal to:
For adiabatic change in a gas:
5 moles of hydrogen initially at STP are compressed adiabatically so that temperature becomes 400°C. Increase in the internal energy of the gas in kilo joules is:(take R=8.3 J/mol-K)
A closed gas cylinder is divided into two parts by a piston held tight. The pressure and volume of gas in two parts respectively are (P, 5V) and (10P, V). If now the piston is left free and the system undergoes isothermal process, then the volume of the gas in two parts respectively are:
In.the figures (a) to (d), variation of volume with change in pressure is shown. The gas is taken along the cyclic path shown by arrows. In which case heat is liberated in the system?
Air in a cylinder is suddenly compressed by a piston which is then maintained at the same position. With the passage of time:
In thermodynamic processes which of the following statements is not true?
A monoatomic gas at pressure P 1 and volume V 1 is compressed adiabatically to 1/8th its original volume. What is the final pressure of the gas?
5.6 litre of the helium gas at STP is adiabatically compressed to 0.7 litre.Taking the initial temperature to be T 1 , the work done in the process is :
A monoatomic gas at a pressure P, having a volume V expands isothermally to a volume 2V and then adiabatically to a volume 16V. The final pressure of the gas is :(take γ = 5/3)
For reversible adiabatic process:
What is the maximum amount of work that can be done by extracting 1J of heat energy from a body at temperature 127 o C with an environment at temperature 27 o C ?
The temperature inside a refrigerator is t 2 °C and the room temperature is t 1 °C The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be :
An engine has efficiency of 1 6 . when temperature of sink is reduced by 62 o C, its efficiency is doubled.Temperature of the source is :
A heat engine employing a Carnot cycle with an efficiency of η = 10 % is used as a refrigerating machine, the thermal reservoirs being the same. The refrigerating efficiency ∈ is:
The change in state of a gas from A to B is as shown in Fig. The work done in the process is:
A carnot engine extracts 1200J of energy from a hot reservoir. What is the amount of work done by it? Temperatures of hot and cold reservoirs are 200K and 150K respectively.
P-V diagram of an ideal gas is as shown in the figure. Work done by the gas in the process ABCD is
What is the relation between work obtained in an reversible and irreversible process?
The two conducting cylinder-piston systems shown below are linked. Cylinder 1 is filled with a certain molar quantity of a monatomic ideal gas, and cylinder 2 is filled with an equal molar quantity of a diatomic ideal gas. The entire apparatus is situated inside an oven whose temperature is T a = 27 ∘ C . The cylinder volumes have the same initial value V 0 = 100 cc . When the oven temperature is slowly raised to T b = 127 ∘ C . . The volume change ∆ v in cc) of cylinder 1 is
A cylinder of cross-section area A has two pistons of negligible mass separated by distances l loaded with spring negligible mass. An ideal gas at temperature T 1 is in the cylinder where the springs are relaxed. When the gas is heated by some means its temperature becomes T 2 and the springs get compressed by l 2 each. If P 0 is atmospheric pressure and spring constant k = 2 P 0 A l then the ratio of T 2 and T 1 is
One mole of a monoatomic gas is brought from state ‘A’ to state ‘B’ along path ACB. Temperature at ‘A’ is ‘To’ Heat absorbed along path ACB is equal To
If the heat of 110 J is added to a gaseous system and change in internal energy is 40 J then the amount of external work done is
An ideal gas undergoes the cyclic process abca as shown in the figure. The internal energy change of the gas along the path ca is – 180 J . The gas absorbs 250 J of heat along the path ab and also absorbs 60 J of heat along the path bc. Find the work done by the gas along the path abc.
An ideal gas at a pressures of 1 atmosphere and temperature of 27 0 C is compressed adiabatically until its pressure becomes 8 times the initial pressure, then the final temperature is ( γ = 3 / 2 ) :
An ideal gas undergoes a process in which co-efficient of volume expansion of gas γ ,varies with absolute temperature by the relation γ = 2 T .Let C is the molar heat capacity in this process and ,C P C V are molar heat capacity at constant pressure and volume respectively. Then
A resistance coil connected with wire to an external battery is placed inside an adiabatic cylinder fitted with a frictionless piston of area of cross-section 5 × 10 − 4 m 2 of mass 5 kg and containing an ideal gas. A current 0.2 A flows through the coil which has a resistance 500 Ω . The constant speed v with which the piston move upwards in order that the temperature of the gas remains unchanged is (P 0 = 105 N/m 2 , g = 10 m/s 2 )
Which of the following statements is correct for any thermodynamic system
A system is provided with 200 cal of heat and the work done by the system on the surrounding is 40 J. Then its internal energy
One mole of O 2 gas having a volume equal to 22.4 litres at 0 o C and 1 atmospheric pressure is compressed isothermally so that its volume reduces to 11.2 litres. The work done in this process is
In isothermal expansion, the pressure is determined by
In isothermic process, which statement is wrong
The isothermal Bulk modulus of an ideal gas at pressure P is
When a gas expands adiabatically
A given system undergoes a change in which the work done by the system equals the decrease in its internal energy. The system must have undergone an
An adiabatic process occurs at constant
One gm mol of a diatomic gas ( γ = 1 .4 ) is compressed adiabatically so that its temperature rises from 27 o C to 127 o C . The work done will be
A gas is being compressed adiabatically. The specific heat of the gas during compression is
The temperature of the sink of a Carnot engine is 27°C. If the efficiency of the engine is 25%, the temperature of the source is
In a thermodynamic process pressure of a fixed mass of a gas is changed in such a manner that the gas molecules give out 30 J of heat and 10 J of work is done on the gas. If the internal energy of the gas was 40 J, then the internal energy wiII be
A system goes from A to B via two processes I and II as shown in fig. If ∆ U 1 and ∆ U 2 are the changes in internal energies in the process I and II respectively, then
A thermodynamic system is taken from state A to B along ACB and is brought back to A along BDA as shown in the P-V diagram. The net work done during the complete cycle is given by the area
A Carnot engine, whose efficiency is 40%, receives heat at 500 K. If its efficiency is 50% then the intake temperature for the same exhaust temperature is
In a thermodynamic process, pressure of a fixed mass of a gas is changed in such a manner that the gas molecules gives out 30 joules of heat and 10 joule of work is done on the gas. If the initial internal energy of the gas was 40 joule, then the final internal energy will be
A sample of ideal monoatomic gas is taken round the cycle ABCA as shown in fig. The work done during the cycle is
A Carnot engine working between 300 K and 600 K has a work output of 800 J per cycle. The amount of heat energy supplied to the engine from the source in each cycle is
A Carnot engine takes in 3000 k- cal of heat from a reservoir at 627°C and gives it to a sink at 27°C. The work done by the engine is
For adiabatic expansion of a monotomic perfect gas, the volume increases by 24%, What is the percentage decrease in pressure ?
A gas is compressed at a constant pressure of 50 N/m 2 from volume of 10 m 3 to a volume of 4 m 3 . Energy of 100 J is then added to the gas by heating. Its internal energy is
A system is given 300 calories of heat and it does 600J of work how much does the internal energy of the system change in this process
In a thermodynamic process the pressure of a fixed mass of gas is altered in such a manner that the gas releases out 20J of heat and at same time 8J of work is done on gas. The change in internal energy of gas is
If the heat of 110 J is added to a gaseous system and change in internal energy is 40 J, then the amount of external work done is :
A system absorbs 1000 cal of heat and does 1675 J of external work. If J = 4.18 J/cal, then the change in internal energy of the system is
A perfect gas goes from state A to another state B by absorbing 8X10 5 J of heat and doing 6X10 5 J of external work. It is now transferred between the same two states in an other process in which it absorbs 10 5 J of heat. In the second process
One gram of water of volume 1 c.c becomes 1671 c.c of steam when boiled at a pressure of one atmosphere. The latent heat of vaporization of water is 540 cal/gm. Find the increase in internal energy (1 at. pressure = 10 5 N/m 2 )
Zeroth law of thermodynamics represents (a) Concept of temperature (b) state of thermal equilibrium of a system (c) that heat is a form of energy
A system absorbs 1000 cal of heat and does 1675 J of external work. If J = 4.18 J/cal, then the change in internal energy of the system is
In a thermodynamics process the pressure of a certain mass of a gas is changed in such a way that 30 J heat is released from it and 10 J work is done on the gas. If the initial internal energy of the system is 30 J then final internal energy is
A system is given 300 calories of heat and it does 600J of work how much does the internal energy of the system change in this process
One gram of water of volume 1 c.c becomes 1671 c.c of steam when boiled at a pressure of one atmosphere. The latent heat of vaporisation of water is 540 cal/gr. Find the increase in internal energy (1 at. pressure = 10 5 N/m 2 )
If a 5 kg body falls to the ground from a height of 30 m and if all its mechanical energy is converted into heat, the heat produced will be
In a given process on an ideal gas, dW = 0 and dQ < 0. Then for the gas :
If a 5 kg body falls to the ground from a height of 30 m and if all its mechanical energy is converted into heat, the heat produced will be
In a thermodynamic process, a system absorbs 2 kilo calorie of heat and at the same time does 500 J of work. What is the change in internal energy of the system :
500 J of heat energy is removed from 4 moles of a monoatomic ideal gas at constant volume. The temperature drops by
A refrigerator with coefficient of performance 1 3 releases 200 J of heat to a hot reservoir. Then the work done on the working substance is
How much heat energy in joules must be supplied to 14 grams of nitrogen at room temperature to raise its temperature by 40° at constant pressure. Molar mass of nitrogen = 28 and R is the gas constant
70 cal of heat are required to raise the temperature of 2 mol of an ideal gas at constant pressure from 30 0 C to 35 0 C. The amount of heat required in calories to raise the temperature of the same gas through the same range (30 0 C-35 0 C) at constant volume is
The gas inside a balloon has a pressure of 8 atmosphere at 27°C. It suddenly bursts. If for the gas C p C v = 1 .5 ,find the resulting temperature.
Ideal monoatomic gas is taken through a process dQ = 2dU. The molar heat capacity for the process is (where dQ is heat supplied and dU is change in internal energy)
The figure shows two paths for the change of state of a gas from A to B . The ratio of molar heat capacities in path 1 and path 2 is
A monoatomic ideal gas, initially at temperature T 1 , is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature T 2 by releasing the piston suddenly. If L 1 and L 2 are lengths of the gas column before and after expansion respectively, then T 1 / T 2 is given by
A refrigerator, whose coefficient of performance β is 4, extracts heat from the cooling compartment at the rate of 400 J per cycle. How much work per cycle is required to operate the refrigerator?
An ideal monoatomic gas undergoes the process AB as shown in the figure. If the heat supplied and the work done in the process are Δ Q and Δ W , respectively. The ratio Δ Q : Δ W is
Heat energy absorbed by a system is going through a cyclic process as shown in figure, is
The internal energy of a gas is given by U = 2 pV . It expands from V 0 to 2 V 0 against a constant pressure ρ 0 . The heat absorbed by the gas in the process is
If a gas expands with temperature according to the relation V = KT 2/3 , then what will be work done when the temperature changes by 30 0 C?
One litre of a gas with γ = 5 3 at NTP is compressed adiabatically to one cubic centimetre, then the resulting pressure is
When heat is supplied to a diatomic gas at constant pressure, then the ratio of Δ Q : Δ U : Δ W will be
The gas inside a balloon has a pressure of 8 atmosphere at 27°C. It suddenly bursts. If for the gas C p C v = 1 .5 ,find the resulting temperature.
A Carnot’s engine has an efficiency of 50% at sink temperature 50 0 C. Calculate the temperature of source.
A Carnot engine has efficiency 25%. It operates between reservoirs of constant temperatures with temperature difference of 80 K. What is the temperature of the low temperature reservoir?
The amount of heat energy required to raise the temperature of 1 g of helium at NTP, from T 1 K to T 2 K is
Which of the following is an equivalent cycle process corresponding to the thermodynamic cyclic process given in the figure , where, 1 2 is adiabatic ( Graphs are schematic and are not to scale)
For which combination of working temperatures of source and sink, the efficiency of Carnot’s heat engine is maximum?
During an adiabatic process of an ideal gas, if p is proportional to 1 V 1.5 then the ratio of specific heat capacities at constant pressure to that at constant volume for the gas is
A refrigerator absorbs 2000 cals of heat from ice trays. If the coefficient of performance is 4, then work done by the motor is
An engineer claims to have made an engine delivering 10 kW power with fuel consumption of 1 g/sec . The calorific value of the fuel is 2 kcal/g . How is the claim of the engineer ?
From the following data, find the magnitude of Joule’s mechanical equivalent of heat. If C p for hydrogen = 3.409 cal g − 1 ∘ C − 1 , C V for hydrogen = 2.409 cal g − 1 ∘ C − 1 and molecular weight of hydrogen =2, then the magnitude of joule’s mechanical equivalent of heat (in Jcal -1 ) will be…….
In the P-V diagram shown in figure ABC is a semicircle. The work done in the process ABC is
The internal energy of gases He, O2 and NH3 are plotted against the absolute temperature. The respective graphs 1, 2 and 3 are of
Carbon monoxide is carried around a closed cycle abc, in which bc is an isothermal process, as shown in the figure. The gas absorbs 7000 J of heat, as its temperature is increased from 300K to 1000K in going from a to b. The quantity of heat rejected by the gas during the process ca is
The average degrees of freedom per molecule of a gas are 6. The gas performs 25J of work when expands at constant pressure. The heat absorbed by the gas is
A sample of 0.1 g of water at 100 0 C and normal pressure 1 . 013 × 10 5 N m – 2 requires 54 Cal of heat energy to convert to steam at 100 0 C . If the volume of the steam produced is 167.1 cc the change in internal energy of the sample, is
In an isothermal process involving change of state, the change in internal energy
When an ideas gas ( γ = 7/3) is heated under constant pressure, then what percentage of given heat energy will be utilised is doing external work
A gas undergoes a process in which the pressure P and volume V are related as VP 2 n − 1 = constant . Find the bulk modulus for the gas.
In the case of ice converted into water
A monoatomic gas at a pressure P, having a volume V expands isothermally to a volume 2V and then adiabatically to a volume 16 V. The final pressure of the gas is (Take γ = 5/3)
A thermodynamic system undergoes cyclic process ABCDA as shown in figure. The work done by the system in the cycle is
A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then
The volume (V) of a monatomic gas varies with its temperature (T) as shown in the graph. The ratio of work done by the gas, to the heat absorbed by it, when it undergoes a change from state A to state B , is
The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is
A refrigerator with coefficient of performance 1/3 releases 200 J of heat to a hot reservoir, then the work done on the working substance is
An ideal monoatomic gas undergoes a cyclic process ABCA as shown in the figure. The ratio of heat absorbed during AB to the work done on the gas during BC is
A gas expands with temperature according to the relation V = KT 1 / 3 . What is the work done when the temperature changes by 30 o C
An insulator container contains 4 moles of an ideal diatomic gas at temperature T. Heat Q is supplied to the gas, due to which 2 moles of the gas are dissociated into atoms but temperature of the gas remains constant.
In which of the following processes, heat is neither absorbed nor released by a system?
In a thermodynamic process pressure of a fixed mass of a gas is changed in such a manner that the gas releases 40 joules of heat and 30 joules of work was done on the gas. If the initial internal energy of the gas was 20 joules, then the final internal energy will be
When a quantity of heat ‘Q’ is supplied to a monoatomic gas work done by the gas is Q 4 Molar heat capacity of the gas in that process is
A refrigerator works between 4 0 C and 30 0 C . It is required to remove 600 calories of heat every second in order to keep the temperature of the refrigerated space constant. The power required is (Take 1 cal = 4.2 Joules)
4.0 g of a gas occupies 22.4 litres at NTP. The specific heat capacity of the gas at constant volume is 5.0 J K – 1 m o l – 1 . If the speed of sound in this gas at NTP is 952 m s – 1 , then the heat capacity at constant pressure is (Take gas constant R = 8.3 J K – 1 m o l – 1 )
The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is -20°, the temperature of the surroundings to which it rejects heat is
The amount of heat energy required to raise the temperature of 1 g of Helium at NTP, from T 1 K t o T 2 K is
The following four wires are made of the same material. Which of these will have the largest extension when the same tension is applied?
During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of C p C υ for the gas is
The following diagram represents a graph between temperature and entropy. Find the efficiency of the engine representing the graph.
In a process the pressure of a gas is inversely proportional to the square of the volume. If the temperature of the gas increases, then work done by the gas
One mole of an ideal monoatomic gas undergoes a process described by the equation p v 3 = c o n s tan t constant. The heat capacity of the gas during this process is
The temperature inside a refrigerator is t 2 0 C and the room temperature is t 1 0 C . The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be
One mole of an ideal diatomic gas undergoes a transition from A to B along a path A B as shown in the figure, The change in internal energy of the gas during the transition is
A system is taken from state a to state c by two paths adc and abc as shown in the figure. The internal energy at a is U a = 10 J . Along the path adc the amount of heat heat absorbed δ Q 1 = 50 J and the work obtained δ W 1 = 20 J whereas along the path abc the heat absorbed δ Q 2 = 36 J . The amount of work along the path abc is
Figure below shows two paths that may be taken by a gas to go from a state A to a state C. In process A B, 400 J of heat is added to the system and process B C, 100 J of heat is added to the system. The heat absorbed by the system in the process A C will be
Which of the following relations does not give the equation of an adiabatic process, where terms have their usual meaning?
In an adiabatic process, when pressure is increased by 2 3 % , I f C P C V = 3 2 , then the volume decreases by about
A Carnot engine absorbs an amount Q of heat from a reservoir at an absolute temperature T and rejects heat to a sink at a temperature of T/3. The amount of heat rejected is
The P-V diagram of 4 gm of helium gas for a certain process A B is shown in the figure. what is the heat given to the gas during the process A B
Thermodynamic processes are indicated in the following diagram.
Two cyclinder A and B of equal capacity are connected to each other via a stop cock. A contains an ideal gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stop cock is suddenly opened. The process is
The efficiency of a Carnot engine depends upon
For an adiabatic expansion process, the quantity PV
P-T curve of the following process will be
In a process V ∝ T 3 , temperature of one mole of a gas is increased by 200k work done by the gas in this process will be
An ideal monoatomic gas is carried around the cycle ABCDA as shown in the figure. The efficiency of the cycle is
Two mole of a diatomic ideal gas is taken through the process PT=constant. Its temperature is increased from T 0 K to 2 T 0 K . Find work done by the system? ( R is gas constant)
An ideal heat engine working between temperature T 1 and T 2 has an efficiency . The new efficiency if both the source and sink temperature are doubled, will be
Carnot’s engine takes in a Thousand Kilo Calories of heat from a reservoir at 827 0 C and exhausts heat to a sink at 27 0 C . How much work does it perform ?
Two moles of a monoatomic gas undergoes an expansion process AB as shown in figure. Then heat supplied to the gas is
The energy density U/V of an ideal mono-atomic gas is related to its pressure P as :
Three moles on an ideal mono-atomic gas perform a cycle shown in figure. The gas temperature at different states are T 1 = 400 k , T 2 = 2400 k a n d T 4 = 1200 k . Heat supplied to the gas is
Three moles of a monoatomic gas are mixed with two moles a diatomic gas. When ‘Q’ amount of heat is supplied to the mixture at constant volume, temperature of the mixture is increased by 30 0 C . Then ‘Q’ is equal to
A mono–atomic gas is expanded from state A to state B according to the process AB as shown in figure. The molar specific heat for the process is
A stationary object at 4° C and weighting 3.5 kg falls from a height 2000 metres on snow mountain at 0° C. If the temperature of the object at the strike is 0° C (g=10 m s – 2 ), then amount of ice melted is:(Latent heat of fusion of ice=3.5× 10 5 J/kg)
A gas has γ =4/3 and is heated at constant pressure, what percentage of total heat supplied is used for doing external work:
How many calories of heat is developed by 200 watt bulb in 5 minutes?
If γ is the ratio of two specific heats of a gas, the number of degrees of freedom of a molecule of the gas is:
A mono atomic gas ( γ =5/3) is suddenly compressed to 1/8th of it’s volume adiabatically then the pressure of the gas will change to (times the initial pressure):
20 grams of a gas occupies 100 cc volume at pressure 10 5 dyne/ c m 2 . If during isothermal process the pressure is changed to 10 4 dyne/ c m 2 , the volume of the gas in cc will be:
When an ideal diatomic gas is heated at constant pressure, the fraction of heat energy supplied which increases the internal energy of the gas is:
One of the most efficient engines ever developed operates between 2100 K and 700 K. It’s actual efficiency is 40%, what percentage of it’s maximum possible efficiency is?
Two cylinders A and B fitted with pistons contain equal amounts of an ideal diatomic gas at 300 K. The piston of A is free to move, while that of B is held fixed. The same amount of heat is given to the gas in each cylinder. If the rise in temperature of the gas in A is 30 K, then the rise in temperature of the gas in B is:
Even Carnot engine cannot give 100% efficiency because we cannot :
A monoatomic ideal gas, initially at temperature T 1 is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature T 2 by releasing the piston suddenly. If L 1 , L 2 are the lengths of the gas column before and after expansion respectively, then T 1 /T 2 is given by :
One mole of an ideal gas requires 207 J heat to raise it’s temperature by 10 K when heated at constant pressure. If the same gas is heated at constant volume the heat required to raise the temperature by 10 K for the same gas, will be : (given R=8.3 J/mol/K)
For the same raise in temperature of two moles of gas at constant pressure, the heat required for triatomic gas is K times the heat required for monoatomic gas. The value of K is
A lead ball moving with a velocity V strikes a wall and stops. If 50% of its energy is converted into heat, then what will be increase in temperature? (specific heat of lead is S)
A mono atomic ideal gas initially at 17 o C is suddenly compressed to one-eighth of its original volume. The temperature after compression is
An ideal gas heat engine operates in carnot’s cycle between 227 o c and 127 o c . If absorbs 6×10 4 cals of heat at higher temperature amount of heat converted to work is
An ideal gas is taken through the cycle A B C A , as shown in figure. If the net heat supplied to the gas in the cycle is 5 J, work done by the gas in the process C A
A rigid container with thermally insulated walls contains a coil resistance 100 Ω carrying current 1 A change in internal energy after 5 minutes will be
PV 3/2 = constant is the relation obeyed by a perfect gas during an adiabatic process, if the initial temperature of the gas is T, then what will be the final temperature of the gas when it is compressed to half of its initial volume.
During an adiabatic process, the pressure of gas is found to be proportional to the cube of its temperature. The ratio of s p e c i f i c h e a t r a t i o γ for the gas is
A gas is taken through the cycle A B C A as shown, what is the net work done
For an adiabatic change, the value of dP P is equal to ….(dv=change in volume, δ = C p C v )
The molar specific heats of an ideal gas at constant pressure and volume are denoted by C P and C V respectively, if δ = C p C v and R is the universal gas constant, then C V is equal to?
A mono atomic gas at a pressure P, having a volume V, expands isothermally to a volume 2V, and then adiabatically to a volume 16 V. The final pressure of the gas is: δ = 5 3
Dry air ( γ = 3 2 ) at atmospheric pressure is suddenly compressed to 1 4 th of its original volume, the pressure will be
The pressure and density of a diatomic gas γ = 7 5 changes adiabatically from ( P,δ ) to ( P 1 ,δ 1 ) . If δ δ 1 = 32 , then P 1 P is:
In an adiabatic process wherein, pressure is increased by 2 3 % if C P C V = 3 2 , Then the volume decreases by about
P–V plots for two gases during adiabatic processes are shown in figure. Plots 1 and 2 should correspond respectively to
A thermodynamic system undergoes a cyclic process ABCDA as shown in figure. The work done by the system is
The temperature of inside and outside of a refrigerator 273 k and 303 k respectively. Assuming that the refrigerator cycle is reversible, for every Joule of work done, the heat delivered to the surrounding will be nearly
A fixed mass of helium gas is made to undergo a process in which its pressure varies linearly from 1 kPa to 2 kPa, in relation to its volume as the latter varies from 0.2 m 3 to 0.4 m 3 . The heat absorbed by the gas will be
Gas in a cylinder moves a piston with area 0.20 m 2 as heat is slowly added to the system. If 2000 J of work is done on the environment by the gas and the pressure of the gas in the cylinder remains constant at 1 x 10 5 Pa, the displacement of the piston must be
A Carnot cycle takes in 1000 J of heat from a source at a high temperature of 400 K. How much heat is rejected to the sink at a lower temperature of 300 K?
For process 1, ∆ U is positive, for process 2, ∆ U is zero and for process 3, ∆ U is negative. Find the parameters indicating x and y axes.
The relation between internal energy U, pressure P and volume V of a gas in an adiabatic process is U = 5 + 3 PV Where a and b are constants. What is the value of the ratio of the specific heats?
One mole of an ideal gas at an initial temperature of T K does 6R. joules of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is 5/3, the final temperature of the gas will be
For an ideal diatomic gas,f process equation is P = b V a (P = Pressure, V = volume, b and a are positive constants). If molar specific heat of process is zero then value of a is
A litre of dry air at STP expands adiabatically to a volume of 3 litres. If γ =1.40, the work done by air is: ( 3 1 . 4 =4.6555) [ Take air to be an ideal gas)
A Carnot engine operates between two reservoirs of temperature 900 K and 300 K. The engine performs 1200 J of work per cycle. The heat energy (in J) delivered by the engine to the low temperature reservoir, in a cycle is .
Internal energy of an ideal gas is given by U=3PV. Then the value of C p C v of the gas is
Under an adiabatic process, the volume of an ideal gas gets doubled. Consequently the mean collision time between the gas molecule changes from τ 1 to τ 2 . If C P C V = γ for this gas then a good estimate for τ 1 τ 2 is given by:
Two ideal Carnot engines operate in cascade(all heat given up by one engine is used by the other engine to produce work) between temperatures, T 1 and T 2 . The temperature of the hot reservoir of the first engine is T 1 and the temperature of the cold reservoir of the second engine is T 2 . T is temperature of the sink of first engine which is also the source for the second engine. How is T related to T 1 and T 2 , if both the engines perform equal amount of work?
A carnot engine operates between temperature limits of 127 o C and 27 o C . If the engine receives 2000 J of heat per cycle from the source, the amount of heat rejected per cycle to the sink is
Efficiency of an engine working on Carnot cycle is 60%. If the temperature of sink is decreased by 25% and that of the source in increased by 25%, then new efficiency of the engine will be
An ideal diatomic gas under goes a thermodynamic process such that the change in its internal energy is Q 3 where Q is the heat supplied to the gas during the process. If ‘C’ be the molar specific heat for the process. Then C =
3 moles of mono atomic ideal gas are mixed with 2 moles of diatomic ideal gas. Then the ratio of C P C V of the mixture is
A thermodynamic cycle xyzx is shown on a V-T diagram The P-V diagram that best describes this cycle is : (Diagrams are schematic and not to scale)
A Carnot engine is operating between temperatures 27 0 C and 127 0 C . Energy received by the engine per second is 40 kJ. Then power out put of the engine is
An ideal monoatomic gas is allowed to expand from state point A to state point B according to the process AB. Then heat supplied to the gas is
Pressure Vs density graph of an ideal gas is shown in figure
Starting at temperature 300 K , one mole of an ideal , diatomic gas γ = 1.4 is first compressed adiabatically from volume V 1 to V 2 = V 1 16 . It is then allowed to expand isobarically to volume 2 V 2 . If all the processes are the quasi-static then the final temperature of the gas (in K ) is (to the nearest integer)
An ideal gas is taken through the process ABC shown in figure. Then
In an isothermal expansion at temperature T, the work done in expanding a gas from volume 2V to 5V is W. The work done in expanding the same gas from 10V to 25V at same temperature 2T will be
A heat engine is involved with exchange of heat of 1915 J, -40J, +125J and -QJ during one cycle achieving an efficiency of 50.0%. The value of Q is:
A balloon filled with helium (32ºC and 1.7 atm.) bursts. Immediately afterwards the expansions of helium can be considered as:
If minimum possible work is done by a refrigerator in converting 100 grams of water at 0 0 C to ice, how much heat (in calories) is released to the surroundings at temperature 27 0 C (Latent heat of ice = 80 cal/gram) to the nearest integer ?
A closed vessel contains 0.1 mole of a monatomic ideal gas at 200 K. If 0.05 mole of the same gas at 400 K is added to it, the final equilibrium temperature (in K) of the gas in the vessel will be close to .
Match the thermodynamic processes taking place in a system with the correct conditions. In the table : Δ Q is the heat supplied, Δ W is the work done and Δ U is change in internal energy of the system.
The change in the magnitude of the volume of an ideal gas when a small additional pressure Δ P is applied at a constant temperature, is the same as the change when the temperature is reduced by a small quantity Δ T at constant pressure. The initial temperature and pressure of the gas were 300 K and 2 atm. respectively. If Δ T = C Δ P then value of C in (K/atm.) is
Three different processes that can occur in an ideal monoatomic gas are shown in the P v s V diagram. The paths are labeled as A B , A C and A D . The change in internal energies during these process are taken as E A B , E A C and E AD and the work done as W A B , W A C and W A D .The correct relation between these parameters are:
In an adiabatic process, the density of a diatomic gas becomes 32 times its initial value. The final pressure of the gas is found to be n times the initial pressure. The value of n is :
Find the external work done by the system in kcal, when 20 kcal of heat is supplied to the system the increase in the internal energy is 8400 J) J = 4200J/kcal)
Air expands from 5 litres to 10 litres at 2 atm pressure. External workdone is
Heat of 30 kcal is supplied to a system and 4200 J of external work is done on the system so that its volume decreases at constant pressure. What is the change in its internal energy. (J = 4200 J/kcal)
Five kilomoles of oxygen is heated at constant pressure. The temperature of the oxygen gas is increased from 295K to 305K. If the molar heat capacity of oxygen at constant pressure is 6.994 kcal/kmole K. The amount of heat absorbed is in kcal,
Choose the false statement. 1st Law of thermodynamics
Two moles of air, when heated through 10 K expands by an amount of 1.66 × 10 –3 m 3 under a constant pressure of 10 5 N/m 2 . If C v = 20.81 J/mole K, then C p is,
Four moles of a perfect gas heated to increase its temperature by 2°C absorbs heat of 40 cal at constant volume. If the same gas is heated at constant pressure the amount of heat supplied is, (R=2 cal/mol K)
Find the change in internal energy in joule. When 10g of air is heated from 30°C to 40°C (Cv = 0.172 kcal/kg K, J = 4200 J/kcal)
The temperature of 5 moles of a gas at constant volume is changed from 100°C to 120°C. The change in internal energy is 80J. The total heat capacity of the gas at constant volume will be in joule/kelvin is
For a gas, the difference between the two specific heats is 4150J Kg -1 K -1 and the ratio of specific heats is 1.4. What is the specific heat of the gas at constant volume in J Kg -1 K -1 ?
The volume of 1 kg of hydrogen gas at N.T.P is 11.2 m 3 . Specific heat of hydrogen at constant volume is 10046J kg –1 K –1 . Find the specific heat at constant pressure in Jkg -1 k -1 .
One mole of O 2 gas having a volume equal to 22.4 litres at 0°C and 1 atmospheric pressure in compressed isothermally so that its volume reduces to 11.2 litres. The work done in this process is
The internal energy of a system changes when it undergoes
The pressure and density of a diatomic gas (γ = 7/5) change adiabatically from (P, d) to (P 1 , d 1 ). If d 1 /d = 32, then P 1 /P should be
A cylinder with a movable piston contains 3 moles of hydrogen at standard temperature and pressure . The walls of the cylinder are made of heat insulator, and the piston is insulated by having a pile of sand on it. The factor of increase of the pressure when the gas is compressed to half its original volume is [given 2 1.4 =2.64]
Which of the processes described below are irreversible ? a) The increase in temperature of an iron rod by hammering it b) A gas in a small container at a temperature T 1 is brought in contact with a big reservoir at a higher temperature T 2 which increases the temperature of the gas c) A quasi-static isothermal expansion of an ideal gas in cylinder fitted with a frictionless piston d) An ideal gas is enclosed in a piston cylinder arrangement with adiabatic walls. A weight W is added to the piston, resulting in compression of gas
The volume (V) of a monoatomic gas varies with its temperature (T), as shown in the graph. The ratio of work done by the gas, to the heat absorbed by it, when it undergoes a change from state A to state B, is
Heat energy absorbed by a system in going through a cyclic process shown in figure is
An ideal gas is taken through a process as shown in the figure. It absorbs 100 J of energy during the process AB. No heat is absorbed or rejected along the process BC and rejectes 140 J during the process CA. During the process BC, 60 J of work is done on the gas. Internal energy of the gas at A is 2000 J. The internal energy at C is
An ideal diatomic gas undergoes an isothermal expansion shown by AB curve in the P-V diagram. The amount of heat absorbed by the gas during this process is (take loge5 = 0.7)
In a mechanical refrigerator, the low temperature coils are at a temperature of – 23°C and the compressed gas in the condenser has a temperature of 27°C. The theoretical coefficient of performance is
Consider the following statements : A) Heat given to an ideal gas under isothermal conditions is used completely to do external work. B) The change in internal energy in a thermodynamic process is independent of the path.
A cannot engine extracts heat from water at 0°C and rejects it to room at 24.4°C. The work required by the refrigerator for every 1 kg of water converted into ice (latent heat of ice = 336kj/kg ) is
3 moles of a monoatomic gas requires 45 cal heat for 5°C rise of temperature at constant volume, then heat required for 5 moles of same gas under constant pressure for 10°C rise of temperature is (R=2 cal/mole/°k)
An ideal gas goes from the state i to the state f as shown in figure. The work done by the gas during the process
The relation between P and T for monoatomic gas during adiabatic process is . The value of C is
A cyclic process is shown in the p-T diagram where line AB is passing through the origin. Which of the curves show the same process on a V-T diagram?
In the figure given two processes A and B are shown by which a thermo-dynamical system goes from initial to final state F. If ΔQ A and ΔQ B are respectively the heats supplied to the system then
When a system is taken from state i to a state f along path iaf, Q = 50J and W = 20 J. Along path fbi, Q = 35J. If w = – 13J for the return path fi, Q for this path is
One mole of diatomic ideal gas undergoes a cyclic process ABCA as shown in figure. The process BC is adiabatic. The temperatures at A,B and C are 400K, 800K and 600K respectively. Choose the correct statement :
The P –V diagram of a system undergoing thermodynamic transformation is shown in figure. The work doneby the gas in going from A→B→C is 50 J and 20 cal heat is given to the system. The change in internal energy between A and C is
The below P-V digram represents the thermodynamic cycle of an engine, operating with and ideal monoatomic gas. The amount of heat extracted from the source in a single cycle is
The variation of pressure P with volume V for an ideal monoatomic gas during an adiabatic process is shown in figure. At point A the magnitude of rate of change of pressure with volume is
Starting with the same initial conditions an ideal gas expands from volume V 1 to V 2 in three different ways. The work done by the gas is W 1 if the process is purely isothermal, W 2 if purely isobaric and W 3 if purely adiabatic. Then
One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure The change in internal energy of the gas during the transition is
A thermodynamic system undergoes cyclic process ABCDA as shown in figure. The work done by the system in the cycle is
An ideal refrigerator has a freezer at a temperature of – 13 0 C . The coefficient of performance of the engine is 5. The temperature of the air (to which heat is rejected) will be
An ideal gas is subjected to a cyclic process involving four thermodynamic states; the amounts of heat (Q) and work (W) involved in each of these states are Q 1 = 6000 J, Q 2 = – 5500 J ; Q 3 = – 3000 J; Q 4 = 3500 J W 1 = 2500 J; W 2 = – 1000 J; W 3 = – 1200 J; W 4 = xJ. The ratio of the net work done by the gas to the total heat abosrbed by the gas is 'η'. The values of x and 'η' respetively are
A heat engine operates by taking n moles of an ideal gas through the cycle ABCDA shown in figure. The thermal efficiency of the engine is (Take Cv = 3R/2, where R is molar gas constant)
One mole of Argon undergoes a process given by PV 3/2 = constant. If heat obtained by gas is Q and molar specific heat of gas in the process is C then which of the following is correct if temperature of gas changes by –26K (assume Argon as an ideal gas)
A monoatomic ideal gas undergoes a process ABC. The heat given to the gas is
Two Carnot engines A and B are operated in series. The engine A receives heat from the source at temperature T 1 and rejects the heat to the sink at temperature T. The second engine B receives the heat at temperature T and rejects to its sink at temperature T 2 . For what value of T the efficiences of the two engines are equal
Consider the process on a system shown in figure. During the process, the work done by the system
A carnot engine has an efficiency of 40%. Keeping the source temperature unchanged, what should be the percentage change in the temperature of the sink in order to increase the efficiency by 10%?
Two ideal gases are enclosed in two piston cylinder arrangements at pressure P 1 and volume V 1 . Now the gases are expanded adiabatically to volume V 2 and their P-V diagrams are as shown in the figure. Then
One mole of a monoatomic gas is expanded isothermally from state A to state B. Then it is compressed isobarically from B to C and finally the gas returns to intial state A following isochoric process CA. Then heat rejected in the process BC is
A gas expands from volume V 1 to volume V 2 according to three different processes 1, 2 and 3. Change in internal energy of the gas in the processes are Δ U 1 , Δ U 2 and Δ U 3 respectively. If same quantity of heat is supplied in three cases, then
If 1 cm 3 of water is vaporized (latent heat of vaporization = 540 cal / g 0 C ) at P = 1 atm. If the volume of steam formed is 1671 cm 3 , calculate increase in internal energy.
The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is
In which of the following processes, heat is neither absorbed nor released by a system?
When 1 kg of ice at 0 0 C melts to water at 0 0 C , the resulting change in its entropy , taking latent heat of ice to be 80 cal / 0 0 C , is
A mono atomic ideal gas at temperature T is expanded adiabatically to eight times its initial volume. Then final temperature of the gas is
Two moles of a diatomic ideal gas is expanded isothermally to twice its original volume. If temperature of the gas is 27 o C and R = 8.3 Joule K-mol , the heat supplied to the gas is Given l n 2 = 0.693
Three moles of hydrogen at 30 o C is allowed to expand at constant pressure to twice its original volume. Then amount of heat supplied to the gas is R = 8.3 J/K-mol
One mole of an ideal monoatomic gas is heated from state point A to state point C according to the process A-B-C as shown in figure. Then total heat supplied to the gas is
When an ideal gas is expanded adiabatically to eight times its initial volume, its temperature is reduced to four times its initial temperature. Then the ratio C V R for the gas is
Efficiency of a carnot engine operating between a source at temperature T 1 and a sink at temperature T 2 is 60%. If a carnot refrigerator operates between the same temperature limits, its coefficient of performance will be
In an adiabatic change, the pressure and temperature of a monoatomic gas are related with relation as P ∝ T C , where C is equal to
A monoatomic ideal gas, initially at temperature T 1 , is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature. T 2 by releasing the piston suddenly. lf L 1 and L 2 are the lengths of the gas column before and after expansion respectively, then T 1 T 2 , is given by
Two identical containers A and B with frictionless pistons contain the same ideal gas at the same temperature and the same volume V. The mass of the gas in A is m A and that in B is m B . The gas in each cylinder is now allowed to expand isothermally to the same final volume 2V.The changes in the pressure in A and.B are found to be P and 1.5 P respectively. Then
A Carnot engine operates with source at 127 0 C and sink at 27 0 C . If the source supplies 40 kJ of heat energy, the work done by the engine is
A gas expands adiabatically at constant pressure such that its temperature T ∝ 1 V , the value of C p C v of gas is
A reversible engine converts one-sixth of the heat input into work. When the temperature of the sink is reduced by 62 0 C , the efficiency of the engine is doubled. The temperatures of the source and sink are
A mass of diatomic gas ( γ = 1 . 4 ) at a pressure of 2 atm is compressed adiabatically so that its temperature rise from 27 0 C to 927 0 C . The pressure of the gas is final state is
A Carnot engine whose sink is at 300 K has an efficiency of 40%. By how much should the temperature of the source be increased so that its efficiency is increased 50% of original efficiency?
For adiabatic processes ( γ = C p C v )
A balloon containing an ideal gas has a volume of l0 litre and temperature of l 7 o . If it is heated slowly to 75″C, the work done by the gas inside the balloon is (neglect elasticity of the balloon and take atmospheric pressure as l 0 5 Pa)
During an adiabatic process the pressure of a gas is found to be proportional to the cube of the absolute temperature. The ratio of the specific heats of the gas is
In an adiabatic process wherein pressure is increased by 2 3 % if C p C v = 3 2 , then the volume decreases by about:
An ideal heat engine working between temperature T H and T L has efficiency η . If both the temperature are raised by 100 K each, the new efficiency of heat engine will be:
An ideal heat engine has an efficiency η . The coefficient of performance of the engine when driven backward will be
A heat engine operates between 2100 K and 700 K. Its actual efficiency is 40%. What percentage of its maximum possible efficiency is this?
In a cold storage, ice melts at the rate of 2 kg/h when the external temperature is 20 0 C . Find the minimum power output of the motor used to drive the refrigerator which just prevents the ice from melting. Latent heat of fusion of ice = 80 cal/g.
A Camot heat engine has an efficiency of 10%. If the same engine is worked backward to obtain a refrigerator, then find its coefficient of performance.
The efficiency of a Carnot cycle is 1 6 . By lowering the temperature of sink by 65 K, it increases to 1 3 . The initial and final temperatures of the sink are
A motor cycle engine delivers a power of l0 kW, by consuming petrol at the rate of 2.4 kg/hour. If the calorific value of petrol is 35.5 MJ/kg, the rate of heat rejection by the exhaust is
A Carnot engine whose low temperature reservoir is at 7 o C has an efficiency of 50%. It is desired to increase the efficiency to 70%.. By how many degrees should the temperature of the high temperature reservoir be increased
An ideal refrigerator has a freezer at a temperature of – 13 0 C . The coefficient of performance of the engine is 5. The temperature of the air (to which heat is rejected) will be
An ideal heat engine working between temperature T 1 and T 2 has an efficiency η , the new efficiency if both the source and sink temperature are doubled, will be
Efficiency of a Carnot engine is 50% when temperature of outlet is 500 K. ln order to increase efficiency up to 60% keeping temperature of intake the same what is temperature of outlet?
A Carnot’s engine is made to work between 200 0 C and O o C first and then between 0 0 C and – 200 0 C . The ratio of efficiencies of the engine in the two cases is
A Camot engine absorbs an amount Q of heat from a reservoir at an absolute temperature T and rejects heat to a sink at a temperature of T 3 . The amount of heat rejected is
A Carnot engine used first an ideal monoatomic gas then an ideal diatomic gas as working substance. If the source and sink temperature are 411 o C and 69 o C respectively and the engine extracts I000 J of heat in each cycle, then area enclosed by the PV diagram is
Efficiency of Carnot engine is 100% if
The efficiency of the reversible heat engine is η r , and that of irreversible heat engine is η l . Which of the following relations is correct?
An ideal gas whose adiabatic exponent equals to 7 5 is expanded according to the law P = 2V.The initial volume of the gas is equal to V o = 1 unit. As a result of expansion the volume increases 4 times. (Take R = units) Column-I Column-II i. Work done by the gas p. 25 units ii. Increment in internal energy of the gas q. 45 units iii. Heat supplied to the gas r. 75 units iv. Molar heat capacity of the gas in the process s. 15 units t. 55 units Now much the given columns and select the correct option from the codes given below. Codes
In an adiabatic process, R = 2 3 C v ,. The pressure of the gas will be proportional to:
The temperature of inside and outside of a refrigerator (working based on carnot cycle) are 273K and 303K respectively. Assuming that the refrigerator cycle is reversible, for every joule of work done, the heat delivered to the surrounding will be nearly :
For an isothermal process, the change in internal energy is
The internal energy ‘U’ is a unique function of any state because change in ‘U ‘:
Thermodynamical system is taken from state A and B along path ACB and is brought back to A along BDA as shown· The net work done during the complete cycle is given by the area:
A system performs work ∆ W when an amount of heat ∆ Q is added to the system. The corresponding change in the internal energy is ∆ U . A unique function of initial and final states irrespective of the mode of change is:
In the condensation of a gas the mean kinetic energy (K) and potential energy ( U) of molecules change; thus:
The internal energy of an ideal gas depends on:
A gas is compressed at a constant pressure of 50 N/m 2 from a volume of 10 m 3 to a volume of 4 m 3 . Energy of 100 J is then added to the gas by heating. Its internal energy is:
In a thermodynamical process pressure of fixed mass of gas is changed in such a way that the gas molecules give out 30 J of heat and 10 J of work is done on the gas. If the internal energy of the gas was 40 J, the final internal energy will be:
A system goes from A to B via two processes I and II as shown in figure. If ∆ U 1 and ∆ U 2 are the changes in internal energies in the processes I and II respectively then
An ideal gas is taken through the cycle A ➔ B ➔ C ➔ A, as shown in the figure. If the net heat supplied to the gas in the cycle is 5 J, the work done by the gas in the process C ➔ A is:
When an ideal diatomic gas is heated at constant pressure,the fraction of the heat energy supplied which increases the internal energy of the gas, is:
540 calories of heat convert l cc of water at 100°C to 1671 cc of steam at 100°C under atmospheric conditions. Increase in internal energy will be nearly:
A diatomic gas contained in a vessel is subjected to a thermodynamic process such that its pressure changes with volume as shown in Fig. Change of internal energy during the process is:
A vessel contains 5 mole of O 2 . The system is given heat at constant pressure. As a result the gas expands and does 120 joule work. Heat given to the gas is:
The internal energy change in a system that has absorbed 2 k cals of heat and done 500 J of work is :
4 gm of He at 27°C is mixed with 16 gm of O 2 at 37°C. If both gases are considered as ideal gases, temperature of the mixture will be nearly:
n moles of an ideal gas expand adiabatically. During this process, temperature changes from an initial value T 1 to a final value T 2 . Work done during the process can be expressed as:
An ideal gas is contained in a vessel. It is heated at constant pressure. Fraction of the heat energy supplied that converts to work done by the gas is:
Heat energy absorbed by a system in going through a cyclic process shown in Fig. 17.35 is:
A thermodynamical process is shown in with P A = 3 X 10 4 Pa; V A = 2 X 10 -3 m 3 ; P B = 8 x 10 4 N/m 2 ; V D = 5 x 10 -3 m 3 .In the processes AB and BC, 600 J and 200 J of heat is added to the system respectively. The change in internal energy of the system in process AC would be:
final volume 4 V through three different thermodynamic processes as shown in Fig.Process 1 is adiabatic, 2 isothermal and 3 isobaric. If ∆ U 1 ∆ U 2 and ∆ U 3 denote the change in internal energy of the gas in the three processes respectively, then:
Two moles of a certain ideal gas at a temperature 300 K were cooled isochorically so that the gas pressure is reduced η (= 2) times. The gas is expanded isobarically afterwards till its temperature got back to original value. The total amount of heat absorbed by gas in this process is:
In a given process on an ideal gas, dW = 0 and dQ < 0. Then for the gas:
In which process net work done is zero? (i) Cyclic (ii) Free expansion (iii) Isochoric (iv) Adiabatic
If in a. thermodynamical process the initial pressure and volume are equal to the final · pressure and volume . respectively, then: (i) the final temperature must be equal to initial (ii) the final internal energy must be equal to initial (iii) the net work done on the system must be zero (iv) the net heat given to the system is zero
A sample of 0.1 g of water at l00°C and normal pressure.(1.013 x 10 5 Nm -2 )requires 54 cal of heat energy to convert to steam at 100°C. If the volume of the steam produced is 167.1 cc, the change in internal energy of the sample, is:
The property of the system that does not change during an adiabatic change is:
The relation between pressure and volume of a given mass of a gas for isothermal change is:
The gas law PV/T = constt. is true for:
The slopes of isothermal and adiabatic curves are related as:
The work done in adiabatic changes in a gas depends only on:
The pressure volume graph of an ideal gas is shown in Fig. The adiabatic processes are:
During the adiabatic expansion of° 2 moles of a gas, the change in internal energy was found to be equal to -100 J. The work done during the process will be equal to:
A monoatomic ideal gas initially at 17°C is suddenly compressed to one-eight of its original volume. The temperature after compression is:
A cycle pump gets hot near the nozzle after a few quick strokes even if they are smooth because:
A container with insulating walls is divided into two equal parts by a partition fitted with a valve. One part is filled with an ideal gas at pressure P and temperature T, whereas the other part is completely evacuated. If the valve is suddenly opened, the pressure and temperature of the gas will be :
The work of 146 kJ is performed in order to compress one kilo mole of a gas adiabatically and in this process the temperature of the gas increases by 7°C. The gas is: R = 8 . 3 J mol – 1 K – 1
During an adiabatic process, the cube of the pressure is found to be inversely proportional to the fourth power of the volume. Then the ratio of specific heats is:
Find the amount of work done to increase the temperature of one mole of an ideal gas by 30°C, if it is expanding under the condition V ∞ T 2 3 : (take R = 8.31 J/mol-K)
6 moles of oxygen, 4 moles of Ar. and 2 moles of water vapour form an ideal gas mixture. The mixture is made to expand adiabatically from an initial temperature 127°C to a final temperature 27°C, decrease of internal energy of the mixture is: (take R=2 cal/mol-K)
A sample of gas expands from volume V 1 and V 2 .The amount of work done by the gas is greatest when the expansion is:
An ideal gas undergoes a process in which its pressure (P) and volume ( V) obey P x V = constant. Bulk modulus of the gas in the process is:
In the graph shown in Fig :
In an adiabatic change, the pressure P and temperature T of a diatomic gas are related by the relation P ∞ T c where c equals:
At 27°C a gas is compressed suddenly such that its pressure becomes (1/8) of its original pressure. Final temperature will be γ = 5 / 3 :
Two samples of air A and B having same composition and initially at the same temperature and pressure are compressed from a volume V to V/2, the sample A isothermally and the sample B adiabatically. The final pressure of:
An ideal gas is initially in the state (P, V,T). If the pressure is increased by an amount dP in an isothermal process, the volume decreases by an amount dV 1 . On the other hand, if the same increase in pressure is given in an adiabatic process from the same initial state, the volume decreases by an amount dV 2 .If dV 1 and dV 2 are small, the ratio dV 1 /dV 2 is:
A monoatomic ideal gas, initially at temperature T 1 , is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature T 2 by releasing the piston suddenly. If L 1 and L 2 are the lengths of gas column before and after expansion respectively, T 1 /T 2 then given by
Starting from the same initial conditions, an ideal gas expands from volume V 1 to V 2 in three different ways. The work done by the gas is W 1 if the process is purely isothermal, W 2 if purely isobaric and W 3 if purely adiabatic.Then:
A mixture contains n 1 moles of monoatomic gas and n 2 moles of diatomic gas. If γ = 1.50, the ratio n 1 : n 2 :
P-V plots for two gases during adiabatic processes are shown in the Fig. Plots 1 and 2 should t correspond respectively to:
During an adiabatic process, the pressure of a gas is proportional to the cube of its absolute temperature. The value of C P C V for the gas is:
One mole of an ideal monoatomic gas undergoes a process described by the equation PV 3 = constant.The heat capacity of the gas during this process is :
A gas is compressed isothermally to half its initial volume.The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then :
Which of the following is an equation of state for an adiabatic process? (i) PV γ = constt . (ii) P / ρ γ = constt . (iii) TV γ – 1 = constt . . (iv) T γ / P γ – 1 = constt . .
One mole of an ideal gas at an initial temperature of T K does 6 R joules of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is 5 3 ,the final temperature of gas will be :
If ∆ U and ∆ W represent the increase in internal energy and work done by the system respectively in a thermodynamical process, which of the following is true?
During an isothermal expansion, a confined ideal gas does 150J of work against its surroundings. This implies that:
A mass of diatomic gas γ = 1 . 4 at a pressure of 2 atmospheres is compressed adiabatically so that its temperature rises from 27°C to 927°C. The pressure of the gas in the final state is :
Ideal gas at pressure P undergoes free expansion from its initial volume of 1.01 litre to 10.1 litre. The final pressure of the gas is?
An engine works between two temperatures 227°C and 27°C. The efficiency of the engine is:
A Carnot engine working between 300 K and 600 K has a work output of 800 J per cycle. The amount of heat energy supplied to the engine from the source in each cycle is:
The temperature inside and outside a refrigerator are 273 K and 303 K respectively. Assume that the refrigeration cycle is reversible. For every joule of work done the heat delivered to the surrounding will be approximately:
A Carnot engine operating between temperatures T 1 and T 2 has efficiency 1 6 . When T 2 is lowered by 62 K, its efficiency 6 increases to 1 3 . Then T 1 and T 2 are, respectively :
A Carnot engine uses first an ideal monoatomic gas γ = 5 3 and then an ideal diatomic gas γ = 7 5 as its working substance. The source and sink temperature are 411°C and 69°C respectively and the engine and the engine extracts 1000 J of heat from the source in each cycle, then :
The ratio W Q for a Carnot engine is 1 6 Now the temperature of o6 sink is reduced by 62 o C, then this ratio becomes twice. The initial temperature of the sink and source are respectively :
An ideal gas heat engine operates in a Carnot cycle between 227 o C and 127 o C. It absorbs 6 kcal at the higher temperature. The amount of heat (in kcal) converted into work is equal to
N moles of a monoatomic gas is carried round the reversible rectangular cycle ABCDA as shown in the diagram. The temperature at A is T o . The thermodynamic efficiency of the cycle is :
A diatomic ideal gas is used in a carnot engine as the working substance. If during the adiabatic expansion part of the cycle the volume of the gas increases from V to 32V, the efficiency of the engine is :
An ideal gas expands isothermally from a volume V 1 to V 2 and then compressed to original volume V 1 adiabatically. Initial pressure is P 1 and final pressure is P 2 . The total work done is W. Then
Which of the following graphs correctly represents the variation of β = – ( dV dP ) V with P for an ideal gas at constant temperature?
An ideal monoatomic gas is taken round the cycle ABCDA as shown in following P-V diagram. The work done during the cycle is
A Camot engine having an efficiency of 1 10 as heat engine, is used as a refrigerator. If the work done on the system is l0 J, the amount of energy absorbed from the reservoir at lower temperature is:
An ideal gas is compressed to half its initial volume by means of several processes. Which of the process results in the maximum work done on the gas?
Figure below shows two paths that may be taken by a gas to go from a state A to a state C. In process AB, 400 J of heat is added to the system and in process BC, 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be
An ideal gas goes from state A to state B via three different processes A as indicated in the p -V I diagram lf Q 1 , Q 2 , Q 3 indicate the heat absorbed P by the gas along the three processes and ∆ U 1 , ∆ U 2 , ∆ U 3 indicate the change in internal energy along the three processes respectively, then
A gas is undergoing an adiabatic process. At a certain stage A, the values of volume and temperature ( V 0 , T 0 ) . From the details given in the graph, find the value of adiabatic constant γ
In the P-V diagram shown in figure, ABC is a semicircle. Find the work done in the process ABC.
Find the work done by gas going through a cyclic process shown in figure?
Figure shows a cyclic process ABCDBEA. performed on an ideal cycle. lf If P A = 2 atm , P B = 5 atm and P c = 6 atm . V E – V A = 20 litre , find the work done by the gas in the complete, process (l atm. pressure = 1 × 10 5 Pa)
P-T curve of a cyclic process is shown. If number of moles of the gas are n, the work done by the gas in the given process is
T-V curve of cyclic process is shown below, number of moles of the gas are n find the total work done during the cycle.
Figure shows the adiabatic curve for n moles of an ideal gas; the bulk’s modulus for the gas corresponding to the point P will be
Adiabatic index of an ideal gas is 1.67. If universal gas constant R = 8.3 Joule/mol-K, value of C v of the gas (in joule/mol-K) is
An ideal gas undergoes a process A B as shown on the pressure- temperature graph. The gas undergoes.
Two moles of an ideal gas is expanded to double its volume by two different processes. One is isobaric and the other one is isothermal. If W 1 and W 2 are the work done respectively, then
One mole of an ideal monatomic gas undergoes the process P = α T 1 / 2 , where α is constant. If molar heat capacity of the gas is β R when R = gas constant, then the value of β is
The efficiency of a carnot engine is 50%. The temperature of the hot reservoir is kept constant. By what amount should the temperature of the cold reservoir be decreased so that efficiency becomes 60%.
Find the work done by the gas in the process ABC.
Two different gases are enclosed in two different identical chambers maintained at common temperature. Their pressures are P 1 and P 2 respectively. The two chambers are connected by a thin pipe keeping the temperature same. Then final pressure is (assuming adiabatic walls)
A diatomic gas ( g = 1.4) does 200 J of work when expanded isobarically. Find the heat given to the gas in the process.
A glass container encloses a gas at a pressure of 8 × 10 5 P a and 300K temperature. The container walls can bear a maximum pressure of 10 6 P a . If the temperature of container is gradually increased, temperature at which the container will break is N × 125 K . Find N.
In an isothermal reversible expansion if the volume of 96gm oxygen at 27 0 C is increases from 70 liters to 140 liters, then the work done by the gas will be
A vessel containing 5 litres of gas at 0.8m pressure is connected to an evacuated vessel of volume 3 litres. The resultant pressure inside will be [Assuming whole lose isolated]
Two identical containers A and B with frictionless pistons contain the same ideal gas at the same temperature and the same volume. The mass of the gas in ‘A’ is m A and that in B is m B . The gas in each cylinder is now allowed to expand isothermal to the same final volume 2v. The change in the pressure in A and B are found to be Δ P and 1.5 Δ P respectively. Then
The isothermal bulk modulus of a perfect gas at normal pressure is
In an isothermal process the volume of an ideal gas is halved. One can say that
The specific heat of a gas in an isothermal process is
A sample of ideal gas is expanded to twice its original volume of 1 m 3 in quasistatic process for which P = α V 2 with α = 3 × 10 5 P a / m 6 as shown in figure. Work done by the expanding gas is
A cylinder filled with a piston contains 0.2 moles of air at temperature 27 0 C. The piston is pushed so slowly that the air within the cylinder remains in thermal equilibrium with surroundings. Find the approximate work done by the system if the final volume is twice the initial volume.
An ideal gas is taken through quasi static process described by P = α V 2 , with α = 5.00 a t m / m 6 . The gas is expanded to twice its original volume of 1 m 3 how much work is done by the gas in expanding gas in this process?
In an adiabatic process R = 2 3 C V . The pressure of the gas will be proportional to
The amount of work done in an adiabatic expansion from temperature T to T 1 is
Pressure- temperature relationship for an ideal gas undergoing adiabatic change is
During an adiabatic expansion of one mole of a gas the change in internal energy was found − 50 J . The work done during the process is
Adiabatic modulus of elasticity of a gas is 2.8 × 10 5 N / m 2 . What will be its isothermal modulus of elasticity. Given C P C V = 1.4
A gas expands with temperature according to the relation V = K T 2 3 .What is the work done when the temperature changes by 30 0 C
In an isochoric process if T 1 = 27 0 C and T 2 = 127 0 C , then P 1 P 2 will be equal to
A sample of gas expands on heating. The amount of work done by the gas is greatest when the expansion is
For the given P-V graph of a diatomic gas find the molar heat capacity of the gas in the process.
In isobaric process, the gas obeys which law of the gas
If 400ml of a gas at 127 0 C is cooled to 7 0 C at constant pressure, Then its final volume will be
The temperature of 5 mol of a gas which was held at constant volume was Changed from 100 0 C to 120 0 C. The change in internal energy was found to be 80J The total heat capacity of the gas at constant volume will be equal to
Work done by air when it expands from 100 litres to 200 litres at a constant pressure of 2 atmosphere is
The ratio of work done by an ideal diatomic gas to the heat supplied by the gas in an isobaric process is
One mole of an ideal gas at temperature T 1 expand according to the l a w p / v = c o n s tan t . Find the work done when the final temperature become T 2 :
The heat supplied to one mole of an ideal mono atomic gas in increasing temperature from T 0 to 2T 0 is 2RT 0 . Find the equation of process to which the gas follows.
A scientist says that the efficiency of his heat engine which operates at source temperature 127 0 C and sink at 27 0 C is 26% then,
An ideal heat engine working between temperature T 1 and T 2 has an efficiency η , the new efficiency if both the source and sink temperature are doubled, will be
A Carnot engine has the same efficiency between 800K to 500K and xk to 600K. The value of x is
A heat engine has an efficiency η . Temperature of source and sink are each decreased by 50k, then the efficiency of the engine
If heat Q is added reversibly to a system at temperature T and heat Q 1 is taken away from it reversibly at temperature T 1 , then which one of the following is correct.
An ideal gas is taken through the cycle A B C A , as shown. If the net heat supplied to the gas in the cycle is 5J, the work done by the gas in the process C A is
P – T curve of a cyclic process is shown. If number of moles of the gas are n, the work done by the gas in the given process is
In a cyclic process of P – V graph pick the wrong choice
An ideal mono atomic gas is taken round the cycle ABCDA as shown in P-V graph. The work done during the cycle is
From the given PV graph, which curve properly represents isothermal process.
What is the Bulk modulus of elasticity of a gas at constant volume?
In isothermal process the gas obey’s which law of the gas
Can two isothermal curves cut each other
Which of the following is a slow process
In the following indicator diagram, the net amount of work done will be
2kg of air is heated at a constant volume. The temperature of air is increased from 293K to 313K. If the specific heat of air at constant volume is 0.718 kJ/kg-k, the amount of heat absorbed in kJ and kcal is, (J = 4.2kcal)
Heat energy absorbed by a system in going through a cyclic process shown in figure is
Carbon monoxide is carried around a closed cycle abc in which bc is an isothermal process as shown in the figure. The gas absorbs 7000J of heat as its temperature 300k to 1000k in going from a to b. The quantity of heat rejected by the gas during the process ca is
The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is
A container that suits the occurrence of an isothermal process should be made of
In adiabatic expansion
In Quasi static process which of the following are represented.
A cyclic process ABCA is shown in the V-T diagram process on the P – V diagram is
In Isothermal expansion, the pressure is determined by
The process in which no heat enter or leaves the system is termed as
Two identical samples of a gas are allowed to expand i) Isothermally ii) Adiabatically. Work done is
In adiabatic expansion of a gas
Δ U + Δ W = 0 is valid for
In a reversible isochoric change
Given P-V graph represents
In isochoric process, the gas obeys which law of the gases.
Thermodynamic processes in nature are
When an ideal diatomic gas is heated at constant pressure, the fraction of the heat energy supplied which increases the internal energy of the gas is
Carnot engine is
When heat is given to a gas in an isobaric process, then
Identify the irreversible process a) Inelastic collision of steel ball b) An extremely slow extension (or) contraction of a spring c) Rapid evaporation
An ideal gas is compressed to half its initial volume by means of several processes. Which of the process results in the maximum work done on the gas ?
Identify Irreversible process 1) Free expansion of gas 2) Radio active process alone 3) Isothermal process
The Radio active decay is process
Radiation of energy from a body is process
Heat produced by the passage of an electric current through a resistance is process
Carnot cycle (reversible) of a gas represented by a P-V curve is shown consider the following statements I. Area ABCD = Work done on the gas II. Area ABCD = Net heat observed III. change in the internal energy in cycle = 0 Which of these are correct.
Free expansion of a gas is process
Sudden expansion of a gas from a container is process
In a cyclic process, the internal energy of the gas
Choose the conditions for Reversibility are : a) There must be complete absence of dissipative forces b) The direct and reverse processes must take place infinitely slowly c) The temperature of the system must not differ appreciably from its surroundings.
For one complete cycle of a thermodynamic process on a gas as shown in the P – V diagram. Which of following is correct
Which of the following is Reversible
Which one of the following is not possible in a cyclic process ?
Free expansion is process
An engineer claims to have made an engine delivering 10kw power with fuel consumption of 1g/s. The calorific value of the fuel is 2k cal/g. Is the claim of the engineer
In free expansion of gas
In free expansion process. a) Work is done on the system b) work is done by the system c) work done is zero.
In free expansion process a) Δ U is positive b) Δ U is negative c) Δ U = 0
In free expansion process a) Δ U = 0 b) Δ Q = 0 c) Δ W = 0 d) Δ U ≠ 0
For free expansion of the gas which of the following is true.
In free expansion process a) Δ Q is positive b) Δ Q is negative c) Δ Q = 0
A Carnot cycle has the reversible processes in the following order.
Specific heat of gas during isochoric process is
An ideal gas has a volume of 3Vat 2 atmosphere pressure keeping the temperature constant, its pressure is doubled. The volume of the gas will be V
A gas at NTP is suddenly compressed to one-fourth of its original volume. It r is supposed to be 3 2 , then the final pressure is atmosphere.
During an adiabatic process, the pressure of a gas found to be proportional to the cube of its absolute temperature. The ratio C P C V for the gas is
The volume of an ideal gas is 1 litre and its pressure is equal to 81cm of mercury column. The volume of gas is made 900cc by compressing it isothermally. The stress of the compressing it isothermally. The stress of the gas will be in mercury.
The pressure and density of a diatomic gas (γ = 7/5 ) change adiabatically from (P, p) to (P’, p’). If P/ P’ = 128 then p’/p is equal to
An ideal gas is expanded so that amount of work done by it is equal to the decrease in internal energy. The gas undergoes the process TV 2/5 = constant the adiabatic compressibility of gas when pressure is P, is:
Figure shows V-T graph of a cyclic process: Which of the following P-V graph represents the same process?
In a Carnot engine, when T 2 = 0 0 C and T 1 = + 200 0 C its efficiency is η 1 and when T 1 = 0 0 C and T 2 = 200 0 C, Its efficiency is η 2 , then what is η 1 / η 2
Three moles of an ideal gas are taken through a cyclic process ABCA as shown on T-V diagram in Fig. The gas loses 2510 J of heat in the complete cycle. If T A = 100 K and T B = 200 K . The work done by the gas during the process BC is….. (Take R = 8.3 JmolK -1 )
In a thermodynamic process pressure of a fixed mass of a gas is changed in such a manner that the gas releases 40 joules of heat and 30 joules of work was done on the gas. If the initial internal energy of the gas was 20 joules, then the final internal energy will be
A cylinder of mass 1kg is given heat of 24000 J at atmospheric pressure. If initially temperature of cylinder is 20°C, then work done by the cylinder will be (Given that Specific heat of cylinder = 400 J kg –1 , Coefficient of volume expansion = 9 x 10 –5 °C –1 , Atmospheric pressure = 10 5 N/m 2 and density of cylinder 9000 kg/m 3 )
An ideal gas heat engine operates in a Carnot cycle between 27°C and 127°C. It absorbs 6 kcal at the higher temperature. The amount of heat (in kcal) converted into work is equal to
A sample of an ideal gas is taken through a cycle a shown in figure. It absorbs 60J of energy during the process AB, no heat during BC, rejects 70J during CA. 40J of work is done on the gas during BC. Internal energy of gas at A is 1500J, the internal energy at C would be
A certain mass of you at 273 k is expanded to 256 times its volume under adiabatic temperature is
When an ideas gas (r = 7/3) is heated under constant pressure, then what percentage of given heat energy will be utilised is doing external work
A gas expands with temperature according to the relation V = KT 1 / 3 . What is the work done when the temperature changes by 30 o C
Two identical containers A and B with frictionless positions contain the same ideal gas at the same temperature and the same volume V. The mass of the gas in A is m A and that of B is m B . The gas in each cylinder is now allowed to expand isothermally to the same final volume 3V. The change in the pressure in A and B are found to be ∆ P and 2.5 ∆ P respectively. Then
A diatomic gas goes through a process ΔU + λW = 0 , now for different value of λ which of the following is incorrect.(W = work done by the gas)
At the middle of the mercury barometer tube there is a little column of air with the length l o and there is vacuum at the top as shown. Under the normal atmospheric pressure and the temperature of 300 kelvin, l 0 = 10cm Neglect expansion of the tube. The length of the air column if the temperature rises to 330 kelvin in equilibrium will be
The pressure and temperature of an ideal gas in a closed vessel are 720 kPa and 40 o C respectively. If 1 4 th of the gas is released from the vessel and the temperature of the remaining gas is raised to 353 o C, the final pressure of the gas is
A thermodynamic system goes from states (i) P 1 , V to 2P 1 , V (ii) P, V 1 to P, 2V 1 . Then work done in the two cases is
A system is given 300 calories of heat and it does 600 joules of work. How much does the internal energy of the system change in this process (J = 4.18 joules/cal)
Which of the following can not determine the state of a thermodynamic system
A thermo-dynamical system is changed from state ( P 1 , V 1 ) to ( P 2 , V 2 ) by two different process. The quantity which will remain same will be
Which of the following is not thermodynamical function
In a thermodynamic process, pressure of a fixed mass of a gas is changed in such a manner that the gas molecules gives out 20 J of heat and 10 J of work is done on the gas. If the initial internal energy of the gas was 40 J, then the final internal energy will be
Out of the following which quantity does not depend on path
A vessel containing 5 litres of a gas at 0.8 m pressure is connected to an evacuated vessel of volume 3 litres. The resultant pressure inside will be (assuming whole system to be isolated)
Temperature is a measurement of coldness or hotness of an object. This definition is based on
The state of a thermodynamic system is represented by
If a system undergoes contraction of volume then the work done by the system will be
For an ideal gas, in an isothermal process
Can two isothermal curves cut each other
A system performs work Δ W when an amount of heat is Δ Q added to the system, the corresponding change in the internal energy is Δ U . A unique function of the initial and final states (irrespective of the mode of change) is
Which of the following is not a thermodynamics co-ordinate
If a gas is heated at constant pressure, its isothermal compressibility
Work done per mol in an isothermal change is
The isothermal bulk modulus of a perfect gas at normal pressure is
In an isothermal process the volume of an ideal gas is halved. One can say that
A thermally insulated container is divided into two parts by a screen. In one part the pressure and temperature are P and T for an ideal gas filled. In the second part it is vacuum. If now a small hole is created in the screen, then the temperature of the gas will
The specific heat of a gas in an isothermal process is
When an ideal gas in a cylinder was compressed isothermally by a piston, the work done on the gas was found to be 1 .5 × 10 4 joules . During this process about
When heat is given to a gas in an isothermal change, the result will be
The work done in an adiabatic change in a gas depends only on
One mole of an ideal gas expands at a constant temperature of 300 K from an initial volume of 10 litres to a final volume of 20 litres. The work done in expanding the gas is (R = 8.31 J/mole-K)
A thermodynamic process in which temperature T of the system remains constant though other variable P and V may change, is called
The volume of an ideal gas is 1 litre and its pressure is equal to 72cm of mercury column. The volume of gas is made 900 cm 3 by compressing it isothermally. The stress of the gas will be
During an isothermal expansion of an ideal gas
A gas at NTP is suddenly compressed to one-fourth of its original volume. If γ is supposed to be 3 2 , then the final pressure is
An ideal gas at 27 o C is compressed adiabatically to 8 27 of its original volume. If γ = 5 3 , then the rise in temperature is
Two identical samples of a gas are allowed to expand (i) isothermally (ii) adiabatically. Work done is
The pressure and density of a diatomic gas ( γ = 7 / 5 ) change adiabatically from (P, d) to (P’, d’). If d ‘ d = 32 , then P ‘ P should be
The slopes of isothermal and adiabatic curves are related as
The amount of work done in an adiabatic expansion from temperature T to T 1 is
During the adiabatic expansion of 2 moles of a gas, the internal energy of the gas is found to decrease by 2 joules, the work done during the process on the gas will be equal to
During the adiabatic expansion of 2 moles of a gas, the internal energy was found to have decreased by 100 J. The work done by the gas in this process is
The adiabatic elasticity of hydrogen gas ( γ = 1 .4 ) at NTP is
Compressed air in the tube of a wheel of a cycle at normal temperature suddenly starts coming out from a puncture. The air inside
A polyatomic gas γ = 4 3 is compressed to 1 8 of its volume adiabatically. If its initial pressure is P 0 , its new pressure will be
For adiabatic processes γ = C p C v
One mole of helium is adiabatically expanded from its initial state ( P i , V i , T i ) to its final state ( P f , V f , T f ) . The decrease in the internal energy associated with this expansion is equal to
Helium at 27 o C has a volume of 8 litres. It is suddenly compressed to a volume of 1 litre. The temperature of the gas will be [ γ = 5 / 3 ]
At N.T.P. one mole of diatomic gas is compressed adiabatically to half of its volume γ = 1.41 . The work done on gas will be
The process in which no heat enters or leaves the system is termed as
Heat is not being exchanged in a body. If its internal energy is increased, then
In a thermodynamic system working substance is ideal gas, its internal energy is in the form of
Which of the following parameters does not characterize the thermodynamic state of matter
For an isothermal expansion of a perfect gas, the value of ΔP P is equal
The gas law PV T = constant is true for
In an isothermal expansion
In an isothermal reversible expansion, if the volume of 96 gm of oxygen at 27°C is increased from 70 litres to 140 litres, then the work done by the gas will be
A container that suits the occurrence of an isothermal process should be made of
If an ideal gas is compressed isothermally then
When 1 gm of water at 0 o C and 1 × 10 5 N / m 2 pressure is converted into ice of volume 1 .091 cm 2 , the external work done will be
A cylinder fitted with a piston contains 0.2 moles of air at temperature 27°C. The piston is pushed so slowly that the air within the cylinder remains in thermal equilibrium with the surroundings. Find the approximate work done by the system if the final volume is twice the initial volume
In adiabatic expansion
An ideal gas A and a real gas B have their volumes increased from V to 2 V under isothermal conditions. The increase in internal energy
If a cylinder containing a gas at high pressure explodes, the gas undergoes
540 calories of heat convert 1 cubic centimeter of water at 100 o C into 1671 cubic centimeter of steam at 100 o C at a pressure of one atmosphere. Then the work done against the atmospheric pressure is nearly
The pressure in the tyre of a car is four times the atmospheric pressure at 300 K. If this tyre suddenly bursts, its new temperature will be ( γ = 1 .4 )
A monoatomic gas ( γ = 5 / 3 ) is suddenly compressed to 1 8 of its original volume adiabatically, then the pressure of the gas will change to
Which is the correct statement?
An ideal gas is expanded adiabatically at an initial temperature of 300 K so that its volume is doubled. The final temperature of the hydrogen gas is ( γ = 1 .40 )
A cycle tyre bursts suddenly. This represents an
In an adiabatic expansion of a gas initial and final temperatures are T 1 and T 2 respectively, then the change in internal energy of the gas is
The adiabatic Bulk modulus of a perfect gas at pressure is given by
For adiabatic process, wrong statement is
Air in a cylinder is suddenly compressed by a piston, which is then maintained at the same position. With the passage of time
If γ denotes the ratio of two specific heats of a gas, the ratio of slopes of adiabatic and isothermal PV curves at their point of intersection is
One mole of an ideal gas requires 207 J heat to raise the temperature by 10 K when heated at constant pressure. If the same gas is heated at constant volume to raise the temperature by the same 10 K, the heat required is
Find the change in internal energy of the system when a system absorbs 2 kilocalorie of heat and at the same time does 500 joules of work
The efficiency of a Carnot engine working between steam point and ice point is
A Carnot engine working between 300 K and 600 K has a work output of 800 J per cycle. The amount of heat energy supplied to the engine from the source in each cycle is
A Carnot engine whose sink is at a temperature of 300 K has an efficiency of 40%, By how much should the temperature of the source be increased so as to increase the efficiency to 60%
An electrical refrigerator abstracts 2000 calories from ice trays. The coefficient of performance is 4. Then the work done by motor in calories is
Heat energy absorbed by a system in going through a cyclic process shown in is
An ideal gas is taken around the cycle ABCA as shown in P-V diagram . The net work done by the gas during the cycle is equal to
A given mass of a gas expands from the state A to the state B by three paths 1, 2 and 3 as shown in fig. lf W 1 ,W 2 and W 3 respectively be the work done by the gas along the three paths, then
In the indicator diagram shown in fig. the net amount of work done is
The efficiency of a Carnot heat engine
An ideal heat engine is working between a source and a sink. The temperatures are raised by 100 K each, the new efficiency of the heat engine will be
The area under the indicator diagram gives
The efficiency of the reversible heat engine is η r and that of irreversible heat engine is η i . Which of the following relations is correct
A Carnot engine operates with a source at 500 K and sink. at 375 K. The engine consumes 600 kcal of heat in one cycle. The heat rejected to the sink per cycle is
In a mechanical refrigerator, the low temperature coils of the evaporator are at -23°C and the compressed gas in t}le condenser has a temperature of 77°C. The coefficient of performance is
The temperature of inside and outside of a refrigerator arc 273 K and 303 K respectively. Assuming that the refrigerator cycle is reversible, for every ioule of work done, the heat delivered to the surrounding will be nearly
An ideal heat engine exhausting heat at 77°C is to have a 30% efficiency. It must take heat at
N moles of a monoatomic gas is carried round the reversible rectangular cycle ABCDA as shown in the fig. The temperature at A is T 0 . The thermodynamic efficiency of the cycle is
A thermodynamical process is shown in the figure (4). The pressures and volumes corresponding to some points in the fig. (4) are P A = 3 × 10 4 PaV A = 2 × 10 − 3 m 3 P D = 8 × 10 4 PaV D = 5 × 10 − 3 m 3 In the process AB,600 J of heat is added to the system and in process 8C,200 | of heat is added to the system. The change in internal energy of the system in process AC would be
A monatomic ideal gas, initially at temperature T 1 , is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature T 2 by releasing the piston suddenly. If L 1 and L 2 are the length of the gas column before and after expansion respectively, then T 1 T 2 is given by
Starting with the same initial conditions, al ideal gas expands from volume V 1 to V 2 in three different ways. The work done by the gas is W 2 if the process is purely isothermal, W 2 if purely isobaric and W 3 if purely adiabatic. Then
An ideal gas is taken through the cycle A B C A as shown in fig. If the net heat supplied to the gas in the cycle is 5 J, the work done by the gas in the process C A is
The temperature-entropy diagram of a reversible engine cycle is given in fig. Its efficiency is
The work of 146 kJ is performed in order to compress one kilomole of a gas adiabatically and in this process the temperature of the gas increases by 7°C. The gas is R = 8 ⋅ 3 J mol − 1 K − 1
Zeroth law of thermodynamics represents (a) Concept of temperature (b) state of thermal equilibrium of a system (c) that heat is a form of energy
A perfect gas goes from state A to another state B by absorbing 8X10 5 J of heat and doing 6X10 5 J of external work. It is now transferred between the same two states in an other process in which it absorbs 10 5 J of heat. In the second process
When heat is added to a system, which of the following is not possible?
In a thermodynamics process the pressure of a certain mass of a gas is changed in such a way that 30 J heat is released from it and 10 J work is done on the gas. If the initial internal energy of the system is 30 J then final internal energy is
A given mass of a gas expands from the state A to B by the three paths 1, 2 and 3. If W 1 , W 2 and W 3 respectively be the work done in three paths, then
The correct statement related to a thermodynamic work W is :
Correct statement among the following is
Pickout the correct statement for the following pairs of work and heat
If the heat of 110 J is added to a gaseous system and change in internal energy is 40 J, then the amount of external work done is :
When heat is added to a system, which of the following is not possible?
A given mass of a gas expands from the state A to B by the three paths 1, 2 and 3. If w 1 , w 2 and w 3 respectively be the work done in three paths, then
In a thermodynamic process the pressure of a fixed mass of gas is altered in such a manner that the gas releases out 20J of heat and at same time 8J of work is done on gas. The change in internal energy of gas is
Pickout the correct statement for the following pairs of work and heat
A gas is at one atmospheric pressure with a volume 800 cm 3 When 100 J of heat is supplied to the gas , it expands to 1 litre at constant pressure. The change in its internal energy is
If amount of heat given to a system be 50 J and work done on the system be 15 J, then change in internal energy of the system is
In a thermodynamic process, a system absorbs 2 kilo calorie of heat and at the same time does 500 J of work. What is the change in internal energy of the system :
While boiling 1 gm of water at pressure 1.013×10 5 N/m 3 , its volume 1471 cm 3 from 1 cm 3 , then work done by the system is
If amount of heat given to a system be 50 J and work done on the system be 15 J, then change in internal energy of the system is
While boiling 1 gm of water at pressure 1.013×10 5 N/m 3 , its volume 1471 cm 3 from 1 cm 3 , then work done by the system is
Boyle’s law is applicable for an [NCERT Exemplar]
In a toy truck the volume of tube is 2000 cc in which air is filed at a pressure 2 × 10 5 N / m 2 . When the tube gets punctured, its volume reduces to 500 cc. Find the number of moles of air leaked out in the puncture. Take atmospheric pressure is 10 5 N/m 2 and atmospheric temperature 27°C.
The given P-V diagram shows expansion of a gas. Which one of the following statement is true?
The pressure and density of a diatomic gas γ = 7 5 change adiabatically from ( P , d ) to P ′ , d ′ . If d ′ d = 32 , then the value of P ′ / P is .
1 mole of gas expands isothermally at 37° C. The amount of heat absorbed by it until its volume doubled is (R = 8.31 mol -1 K -1 )
On an isothermal process, there are two points A and B at which pressures and volumes are (2P 0 , V 0 ) and (P 0 , 2V 0 ) respectively. If A and B are connected by a straight line. find the pressure at a point on this straight line at which temperature is maximum:
A Carnot engine has the same efficiency between 800 K to 500 K and x K to 600 K. The value of x is
In the cyclic process as shown is the figure. The work done by the gas in one cyclic process is
70 calories of heat is required to raise the temperature of 2 moles of an ideal diatomic gas at constant pressure from 30° C to 35° C . The amount of heat required (in calories) to raise the temperature of the same gas through the same range(30°C to 35°C) at constant volume is
The relation dU = nC v dT for ideal gas is valid for the process
One mole of ideal gas expands isobarically to double its volume at 27°C. Then the work done by the gas is nearly
One mole of an ideal monoatomic gas is compressed such that its temperature increases from 0°C to 100°C. Work done by the gas is
0.5 moles of diatomic gas at 27°C is heated taken through an isothermal process , so that its volume is doubled. If R = 8.3 J/mole/K. Find the work done in this process
500 J of heat energy is removed from 4 moles of a monoatomic ideal gas at constant volume. The temperature drops by
How much heat energy in joules must be supplied to 14 grams of nitrogen at room temperature to raise its temperature by 40° at constant pressure. Molar mass of nitrogen = 28 and R is the gas constant
One mole of ideal gas expands isobarically to double its volume at 27°C. Then the work done by the gas is nearly
One mole of an ideal monoatomic gas is compressed adiabatically so that its temperature increases from 0°C to 100°C. Work done by the gas is
A refrigerator absorbs 2000 cals of heat from ice trays. If the coefficient of performance is 4, then work done by the motor is
A gas for which γ = 1.5 is suddenly compressed to the 1 4 th of the initial volume. Then the ratio of the final to the initial pressure is
A Carnot engine has the same efficiency between 800 K to 500 K and x K to 600 K. The value of x is
1 moles of diatomic gas at 27°C is heated at constant temperature, so that its volume is doubled. If R = 8.3 J/mole/K. Find the work done in this process
In the cyclic process as shown is the figure. The work done by the gas in one cyclic process is
A sample of certain gas is allowed to expand to twice the initial volume (a) Isothermally and then (b) adiabatically, then the final pressure (P f ) and the change of pressure ( Δ p) are such that
70 calories of heat is required to raise the temperature of 2 moles of an ideal diatomic gas at constant pressure from 30° C to 35° C . The amount of heat required (in calories) to raise the temperature of the same gas through the same range(30°C to 35°C) at constant volume is
The relation dU = nC v dT for ideal gas is valid for the process
The value of γ = C P / C V is 4/3 for an adiabatic process of an ideal gas for which internal energy U = K + nPV . The value of n ( K is a constant ) is .
The pressure of a monoatomic gas increases linearly from 4 × 10 5 N / m 2 to 8 × 10 5 N / m 2 when its volume increases from 0.2 m 3 to 0.5 m 3 . The work done by the gas is
Internal energy a given mass of an ideal gas depends
310 J of heat is required to raise the temperature of 2 moles of an ideal gas at constant pressure from 25°C to 35°C. The amount of heat required to raise the temperature of the gas through the same range at constant volume is
The slope of isothermal and adiabatic curves are related as
The efficiency of a Carnot engine working between source temperature T and sink temperature 27°C is 25%. The source temperature T is
The pressure of a monoatomic gas increases linearly from 4 × 10 5 N / m 2 to 8 × 10 5 N / m 2 when its volume increases from 0.2 m 3 to 0.5 m 3 . The work done by the gas is
The heat energy absorbed by a system in going through a cyclic process shown in figure is
The second law of thermodynamics implies
P-V plots for two gases during adiabatic processes are shown in the figure. Plots 1 and 2 should correspond respectively to
Ideal monoatomic gas is taken through a process dQ = 2dU. The molar heat capacity for the process is (where dQ is heat supplied and dU is change in internal energy)
310 J of heat is required to raise the temperature of 2 moles of an ideal gas at constant pressure from 25°C to 35°C. The amount of heat required to raise the temperature of the gas through the same range at constant volume is
The work done in an isothermal expansion of a gas depends upon
A gas is heated at constant pressure. The fraction of heat energy used to increases the internal energy of the gas molecules is
During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of C p C v for the gas is
A cyclic process is shown on the V – T diagram. The same process on a P – T diagram is shown by
P-V plots for two gases during adiabatic processes are shown in the figure. Plots 1 and 2 should correspond respectively to
The efficiency of Carnot engine is 50% and temperature of sink is 500 K. If the temperature of source is kept constant and its efficiency is to be raised to 60% then the required temperature of sink will be
A Carnot engine works first between 200° C and 0° C and then between 0° C and – 200° C. The ratio of its efficiency in these two cases is
A cyclic process is shown on the V – T diagram. The same process on a P – T diagram is shown by
At 27°C two moles of an ideal gas ( γ = 3 / 2 ) occupy a volume V. The gas expands adiabatically to a volume 2V. Final temperature of the gas approximately is
The efficiency of a Carnot engine working between source temperature T and sink temperature 27°C is 25%. The source temperature T is
The slope of isothermal and adiabatic curves are related as
The work done in an isothermal expansion of a gas depends upon
The second law of thermodynamics implies
A gas is heated at constant pressure. The fraction of heat energy used to increases the internal energy of the gas molecules is
The heat energy absorbed by a system in going through a cyclic process shown in figure is
During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of C p C v for the gas is
1 mole of a gas having γ = 7 5 is mixed with 1 mole of a gas having γ = 4 3 . What will be the γ for the mixture?
A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then
1 mole of a gas having γ = 7 5 is mixed with 1 mole of a gas having γ = 4 3 . What will be the γ for the mixture?
An ideal refrigerator has freezer at a temperature of -13°C. The coefficient of performance of the engine is 5. The temperature of the air (to which heat is rejected) will be
A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then
The efficiency of Carnot engine is 50% and temperature of sink is 500 K. If the temperature of source is kept constant and its efficiency is to be raised to 60% then the required temperature of sink will be
A monoatomic gas is supplied the heat Q very slowly keeping the pressure constant. The work done by the gas will be
ρ -V diagram of a diatomic gas is a straight line passing through origin. The molar heat capacity of the gas in the process will be
Two pistons can move freely inside a horizontal cylinder having two sections of unequal cross-sections. The pistons are joined by an inextensible, light string and some gas is enclosed between the pistons. On heating the system, the piston will
Ideal monoatomic gas is taken through a process dQ = 2 dU . The molar heat capacity for the process is (where, dQ is heat supplied and dU is change in internal energy)
The pressure (1 X 10 5 Nm -2 ) of the air filled in a vessel is decreased adiabatically so much as to increase its volume three times. The air pressure is ( γ for air = 1.4, log 10 3 = 0.4771, log 10 2.148= 0.33206)
A Carnot engine works first between 200° C and 0° C and then between 0° C and – 200° C. The ratio of its efficiency in these two cases is
An ideal refrigerator has freezer at a temperature of -13°C. The coefficient of performance of the engine is 5. The temperature of the air (to which heat is rejected) will be
The volume of a gas changes from 2 litre to 10 litre at constant temperature 300 K: The change in internal energy will be:
During an adiabatic process, the cube of the pressure is found to be inversely proportional to the fourth power of the volume. Then, the ratio of specific heats is
A diatomic gas, having C 0 = 7 2 R and C v = 5 2 R is heated at constant pressure. The ratio dU : dQ : dW
During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of C p C V for the gas is
A cylinder of fixed capacity (of 44.8 L) contains 2 mol of helium gas at STP. What is the amount of heat needed to raise the temperature of the gas in the cylinder by 20°C? (Take, R = 8.31J mol -1 K -1 )
A mixture contains n 1 moles of monoatomic gas and n 2 moles of diatomic gas. If γ = 1.50, the ratio n 1 : n 2 :
When water is boiled under a pressure of 2 atm, the heat of vaporization is 2.20 × 10 6 Jkg − 1 and the boiling point is 120°C. At this pressure, 1 kg of water has a volume of 10 -3 m 3 and 1 kg of steam has a volume of 0.824 m 3 . What is the work done when 1 kg of steam is formed at this temperature?
The change in state of a gas from A to B is as shown in Fig. The work done in the process is:
