| Top Physics Questions |
| Equal masses of three liquids A, Band C have temperatures 10°C, 25°C and 40°C respectively. If A and B are mixed, the mixture has a temperature of 15°C. If B and C are mixed, the mixture has a temperature of 30°C. If A and Care mixed, the mixture will have a temperature of: |
A particle is projected from the ground with an initial velocity of 20 m/s at an angle of 30° with horizontal. The magnitude of change in velocity in a time interval from t = 0 to t o = 0.5 s is : (g = 10 ms -2 ) |
| The velocity of a body moving in viscous medium is given by V = A B [ 1 − e − t / B ] where t is time, A and B are constants. Then the dimensional formula of A is |
A ball of mass 5kg hangs from a spring of force constant k N/m and oscillates with certain time period. If the ball is removed, the spring shortens by |
| The maximum intensity in Young’s double slit experiment is I 0 . Distance between the slits is d = 5 λ , where λ is the wavelength of monochromatic light used in the experiment. The intensity of light in front of one of the slits on a screen at a distance D = 10d is |
The length of a strip measured with a metre rod is 10.0 cm. Its width measured with a vernier calipers is 1.00 cm. The least count of the metre rod is 0.1 cm and that of vernier calipers is 0.01 crn. What will be error in its area? |
| A physical quantity is represented by X = M a L b T c . If percentage errors in the measurement of M, L and T are α , β and γ respectively, then total percentage error is |
In the circuit shown in Fig. the reading of the ammeter is (assume internal resistance of the battery be to zero) |
| A body of mass 2 kg is being dragged with uniform velocity of 2 m/s on a rough horizontal plane. The coefficient of friction between the body and the surface is 0.20. The amount of heat generated in 5 sec is J = 4 .2 joule / cal and g = 9 .8 m / s 2 |
The momentum of a photon of energy 1 MeV in kg m/s will be |
| An oscillating simple pendulum is arranged in a vacuum jar, then |
What is the depth at which the value of acceleration due to gravity becomes 1/ n times the value that the surface of earth? (Radius of earth =R) [NEET 2020] |
| A lift performs the first part of ascent with uniform acceleration a and the remainder with uniform retardation 2a. The lift starts from rest and finally comes to rest. If t is the time of ascent. Find the height ascended by lift. |
In the circuits shown below, the readings of the voltmeters and the ammeters will be |
| A block of mass m is tied to one end of a string of length l, young’s modulus Y and cross-sectional area A. The block is made to rotate in a horizontal circle of radius l with angular velocity ω in a gravity free space. If elongation of the wire is x, then elastic potential energy stored in the wire is |
Consider a vertical parallel of semi-circular cross-section dipped in a liquid. Assume that the wetting of the tube is complete. The force of surface tension on the flat part and on curved part of the tube are in the ratio |
| A particle with restoring force proportional to displacement and resisting force proportional to velocity is subjected to a force. If the amplitude of a particle is maximum for frequency while the energy is maximum for the frequency then (where = natural frequency of oscillation of particle) |
Three positive charges of equal value q are placed at the vertices of an equilateral triangle. The resulting lines of force should be sketched as in |
| When a 4 kg mass is hung vertically on a light spring that obeys Hooke’s law, the spring stretches by 2 cm. The work required to be done by an external agent in stretching this spring by 5 cm will be (g = 9.8 metre/ sec 2 ) |
Acceleration due to gravity on the surface of the earth is g = GM R 2 . The gravitational constant G is exactly known. But percentage error in measurement of the mass of earth M and radius of the earth R are 1% and 2%. Respectively. The maximum percentage error in measurement of acceleration due to gravity on the surface of the earth in n%. Find the value of n. |
| A particle is subjected to two simple harmonic motions in the same direction having equal amplitudes and equal frequency. If the resulting amplitude is equal to the amplitude of individual motions, the phase difference between them is |
A convex lens A of focal length 20 cm and a concave lens B of focal length 5 cm are kept along the same axis with the distance d between them. If a parallel beam of light falling on A leaves B as a parallel beam, then distance d in cm will be |
| Frequency of oscillation of a block with two springs separately are 3Hz and 4Hz. Frequency of oscillation of same block with both springs connected in parallel is |
A body starts from rest and moves with constant acceleration the ratio of the distance covered in the nth second to that covered in ‘n’ seconds is |
| The electric field associated with a light wave is E = E 0 sin 1 ⋅ 57 × 10 7 ( x − c t ) where x is in metre and t is in second. If this light is used to produce photo-electric emission from the surface of a metal of work-function 1’9 eV, then the stopping potential will be |
Two charged particles having charges 1 μC and – 1 μC and of mass 50 g each are held at rest while their separation is 2 m. Now the charges are released. Find the speed of the particles when their separation is 1 m. |
| A vessel of area of cross-section A has liquid to a height H . There is a hole at the bottom of vessel having area of cross-section a . The time taken to decrease the level from H 1 to H 2 will be: |
In the given circuit diagram, initially the switch S is opened. Find heat dissipated in the circuit (in mJ) after switch S in closed. It is given C = 2 μF . |
| Statement I: In the relation f = 1 2 l T m , where symbols have standard meaning, m represent linear mass density. Statement II: The frequency has the dimensions of inverse of time. |
A hoop of mass 500gm & radius 10cm is placed on a nail. then the moment of inertia of the hoop, when it is rotated about the nail will be– kgm 2 |
| When a solid cylinder of radius R is subjected to an axial tensile force, the elongation produced in it is found to be x. When a hollow cylinder of inner radius R and outer radius y, made of same material and having same length is subjected to same tensile axial force, Then elongation produced in it is found to be x. Then the value of y R is |
The velocity of a body moving along x direction is related to its displacement as 3 x 2 – 2 x . Acceleration of the body at x=2 m is |
| A projectile passes two points A and B at same height after 2 s and 6 s of its projection. Horizontal separation between the points A and B is 120 m. The horizontal range is closest to:[g=10m/s 2 ] |
An electron of mass m and a photon have same energy E . The ratio of de-Broglie wavelengths associated with them is |
| A soap bubble is being blown at the end of a very narrow tube of radius b. Air (density ρ ) moves with a velocity ‘v’ inside the tube and comes to rest inside the bubble. The surface tension of the soap solution is T. After some time the bubble, having grown to a radius ‘r’, separates from the tube. Find the value of ‘r’. Assume that r>>b so that you can consider the air to be falling normally on the bubble’s surface. |
Two capillary of length L and 2L and of radius R and 2R are connected in series. The net rate of flow of fluid through them will be (given rate of the flow through single capillary, X = πPR 4 / 8 ηL ) |
| Consider the quantities: pressure, power, energy, impulse, gravitational potential, electrical charge, temperature, area. Out of these, the only vector quantities are |
A parallel beam of light strikes a piece of transparent glass having cross section as shown in the figure below. Correct shape of the emergent wavefront will be (figures are schematic and not drawn to scale)- |
| (A) comets move around the Sun in elliptical orbits. The gravitational force acting on the comet due to Sun is not normal to the comets velocity but the work done by the gravitational force over every complete orbit of the comet is zero. ( R) Gravitational Force is a non conservative force. |
A ball of mass m moves with speed v and it strikes normally with a wall and reflected back normally, if its time of contact with wall is t then find force exerted by ball on wall |
| There are three thermometers one in contact with the skin of the man, other in between the vest and the shirt and third in between the shirt and coat. The readings of the thermometers are 30 o C,25 o C and 22 o C, respectively. If the vest and the shirt are of the same thickness, the ratio of their thermal conductivities is |
A heavy mass is attached to a thin wire and is whirled in a vertical circle. The wire is most likely to break |
| If on the concentric hollow spheres of radii r and R (>r) the charge Q is distributed such that their surface densities are same then the potential at their common centre is |
In a car the engine supplies power to front wheels only and brakes are applied to all four wheels. The front wheels support 3/5 of car’s weight on road. If the coefficients of static and kinetic frictions between tyres and road are 0.6 and 0.4 respectively, the maximum rate at which the velocity can change with respect to time is (in m/s 2 ) |
| Which of the following graph represents the variation of resistivity ( ρ ) with temperature (T) for copper? |
Given a number of capacitors labelled as C,V. Find the minimum number of capacitors needed to get an arrangement equivalent to C net , V net |
| The magnetic moment of a bar magnet is 3.6×10 -3 A.m 2 . Its pole strength is 120 milli amp. m. Its magnetic length is |
A bob of a simple pendulum of mass
40 gm with a positive charge 4 x 10 – 6 C is oscillating with time period ‘ T 1 ‘. An electric field of intensity 3.6 x 10 4 N/c is applied vertically upwards now time period is T 2 . The value of T 2 T 1 is (g=10 m / s – 2 ) |
| When a tuning fork A of unknown frequency is sounded with another tuning fork B of frequency 256 Hz, then 3 beats per second are observed. After that A is loaded with wax and sounded, the again 3 beats per second are observed. The frequency of the tuning fork A is |
If the amplitude ratio of two sources producing interference is 3 : 5, the ratio of intensities at maxima and minima is |
| A child is sitting at one end of a long trolley moving with a uniform speed v on a smooth horizontal track. If the child starts running towards the other end of the trolley with a speed u (w.r.t trolley), the speed of the center of mass of the system will |
Two forces are acting on a rope lying on a smooth table as shown in figure. Which of the following statement (s) is/are correct? I. In moving from A to B, tension on string decreases from 2F to F. II. Situation will becomes indeterminant, if we take it a massless string. |
| A slit of size 0.15 cm is placed at 2.1 m from a screen. On illuminated it by a light of wavelength 5 × 10 –5 cm. The width of central maxima will be |
In the following figure, the pulley P 1 is fixed and the pulley P 2 is movable. lf W 1 = W 2 = 100 N, what is the angle A P 2 P 1 ? The pulleys are frictionless. |
| If λ m denotes the wavelength at which the radiative emission from a black body at a temperature T K is maximum, then |
The Number of significant figures in 0.0006032 is |
| If the width of the slit used in single slit Fraunhoffer diffraction is increased then the intensity of the central bright fringe |
A uniform square plate has a small piece Q of an irregular shape removed and glued to the centre of the plate leaving a hole behind in figure. The moment of inertia about the z-axis is then, |
| The magnitude energy of electron of hydrogen atom in a stationary orbit of radius r n is proportional to |
A pendulum of mass m and length L is connected to a spring as shown in figure. If the bob is displaced slightly from its mean position and released, it performs simple harmonic motion. The angular frequency of the oscillation of bob is |
| A ray of light is incident on a transparent slab of glass having refractive index 3 . A part of incident energy is reflected and the balance amount of energy is refracted into the slab. If the angle between refracted and reflected rays is 90 o , what is the angle of deviation of the reflected ray? |
The base current of a transistor is 105 μ A and the collector current is 2.05mA. Then β of the transistor is |
| The dimensional formula of the ratio of angular to linear momentum is |
A particle starts from rest. a(m/s 2 ) Its acceleration (a) versus time (r) is as shown in the Figure. The maximum speed of the particle will be: |
| The depletion layer in the p-n junction region is caused by |
Two long parallel wires, AB and CD, carry equal currents in opposite directions. They lie in the xy plane, parallel to the x-axis, and pass through the points (0, –1, 0) and (0, 1, 0) respectively. The resultant magnetic field is |
| Two identical sinusoidal waves with wave lengths of 3.00 m travel in the same direction at a speed of 2.00 m/s. The second wave originates from the same point as the first, but at a later time. The amplitude of the resultant wave is the same as that of each of the two initial waves. Determine the minimum possible time interval (in sec) between the starting moments of the two waves. |
A horizontal pipe of non-uniform cross-section allows water to flow through it with a velocity1 m s − 1 when pressure is 50 kPa at a point. If the velocity of flow has to be 2 m s − 1 at some other point, the pressure at that point should be |
| Two masses A and B are connected with two inextensible string to write constraint relation between v A and v B Student A: v A cos θ = v B Student B: v B cos θ = v A |
A block of mass m is suspended vertically with a spring of spring constant k. The block is made to oscillate in a gravitation field. Its time period is found to be T. Now the space between the plates is made gravity free, and an electric field E is produced in the downward direction. Now the block is given a charge q. The new time period of oscillation is |
| A cylindrical conductor is placed near another positively charged conductor. The net charge acquired by the cylindrical conductor will be |
Two boys are standing at the ends A and B of a ground where ,AB – a The boy at B starts running in a direction perpendicular to AB with velocity v 1 . The boy at A starts simultaneously with velocity y as shown in figure and catches the other boy in a time t, where t is |
| Using mass (M), length (L), time (T), and electric current (A) as fundamental quantities, the dimensions of permittivity will be |
In a common base configuration the emitter current changes by 5mA when emitter voltage is changed by 200 mV at a fixed collector to base voltage. The input resistance is |
| Pickout the correct statement for the following pairs of work and heat |
The current in the circuit of fig.is |
| A concave mirror of focal length 20cm (in air) is immersed in water ( μ = 4/3). The focal length of the mirror in water will be |
A uniform rod of length l is suspended from any point P. It is then made to undergo small oscillations. If P is the |
| Can pressure p , density ρ and velocity v be taken as fundamental quantities? |
Which among the following shows the particle nature of light? |
| An ideal heat engine has an efficiency η . The coefficient of performance of the engine when driven backward will be |
A device which converts electrical energy into mechanical energy is |
| A car covers the first half of the distance between the two places at 40 kmh – 1 . and another half at 60 kmh – 1 . The average speed of the car is |
A faulty thermometer has its lower fixed point marked as -10º C and upper fixed point marked as 110°.If the temperature of the body shown in this scale is 62°, the temperature shown on the Celsius scale is |
| A cylindrical vessel contains a liquid of density ρ up to a height h . The liquid is closed by a piston of mass m and area of cross-section A . There is a small hole at the bottom of the vessel. The speed v with which the liquid comes out of the hole is: |
Two stones having different masses m 1 and m 2 are projected at an angle α and (90° – α ) with same speed from same point. The ratio of their maximum heights is |
| If f(x) = sin 3 x – cos(2x), then the value of f π 2 is : |
In the circuit shown below E 1 = 4.0 V, R 1 = 2 Ω , E 2 = 6.0 V , R 2 = 4 Ω , and R 3 = 2 Ω current I 1 is : |
| A mass m is attached to a thin wire and whirled in a vertical circle. The wire is most likely to break when |
The resistance between A and B is |
| An open tank 10 m long and 2 m deep is filled up to 1.5 m height of oil of specific gravity 0.82. The tank is uniformly accelerated along its length from rest to a speed of 20 m/s horizontally. The shortest time in which the speed may be attained without spilling any oil is |
If the velocity v of a particle moving along a straight line decreases linearly with its displacement s from 20 m/s to a value approaching zero at s = 30 m figure, then acceleration of the particle at s = 15 m is |
| A block of mass m = 11. 7 kg is to be pushed a distance of s = 4.65 m along an incline and raised to a distance of h = 2.86 m. Assuming frictionless surface, calculate the work done in applying a force parallel to the incline to push the block up at a constant speed. (Take, g = 9.8 ms – 2 ) |
Two wires of equal diameters, of resistivities ρ 1 and ρ 2 and lengths l 1 and l 2 , respectively, are joined in series. The equivalent resistivity of the combination is |
| A piston of cross-sectional area 100 cm 2 is used in a hydraulic press to exert a force of 10 7 dyne on the water. The cross-sectional area of the other piston which supports an object having a mass 2000 kg is: |
A wooden block is floating in a water tank. The block is pressed to its bottom. During the process, work done is equal to: |
| A projectile is given an initial velocity of i ^ + 2 j ^ . The Cartesian equation of its path is: ( g = 10 m / s 2 ) |
A spring has a certain mass suspended from it and its period for vertical oscillations is T 1 The spring is now cut into two equal halves and the same mass is suspended from one of the halves. The period of vertical oscillations is now T 2 The ratio of T 2 / T 1 is |
