Thermodynamics MCQ Class 11 Physics

MCQs (Multiple Choice Questions) are a crucial part of exam preparation for Class 11 Physics, helping students build a strong foundation for board exams and competitive tests like NEET and JEE. They simplify complex topics, ensure thorough practice, and make it easier to identify and address learning gaps.

Thermodynamics MCQ Class 11 Physics provides students with an excellent way to master key concepts in thermodynamics, such as heat transfer, laws of thermodynamics, and the principles of work and energy in thermal systems. By solving these thermodynamics MCQ class 11 questions, students can develop a deeper understanding of critical topics while preparing to tackle challenging questions confidently.

The chapter on Thermodynamics is fundamental for grasping topics like heat engines, entropy, and thermodynamic processes, which are widely applied in real-world scenarios. With resources like thermodynamics class 11 physics mcq pdf, thermodynamics mcq questions pdf, and step-by-step solutions, students can effectively enhance their problem-solving skills and solidify their understanding.

Whether you are preparing for school exams, class quizzes, or competitive tests, these MCQs are designed to make learning engaging and efficient. Utilize the Thermodynamics MCQ Class 11 Physics resources to excel in this essential topic and achieve academic success.

Class 11 Physics Laws of Motion Overview

Thermodynamics is a branch of physics that deals with the relationships between heat, work, and energy. It is a vital topic in physics as it connects macroscopic and microscopic phenomena, providing a deeper understanding of natural processes. Below is an overview of the key concepts covered in this chapter:

Key Concepts in Thermodynamics

1. Thermodynamic Systems and Surroundings

• A system refers to the part of the universe chosen for analysis, while everything outside the system is its surroundings.
• Types of systems:
  • Open System: Exchanges both energy and matter with surroundings.
  • Closed System: Exchanges only energy, not matter.
  • Isolated System: Exchanges neither energy nor matter.

2. State Variables and Processes

• State Variables: Properties such as pressure (P), volume (V), temperature (T), and internal energy (U) that define the state of a system.
• Thermodynamic Process: A system undergoes changes from one equilibrium state to another. Types of processes include:
  • Isothermal Process: Constant temperature.
  • Adiabatic Process: No heat exchange.
  • Isochoric Process: Constant volume.
  • Isobaric Process: Constant pressure.

3. Zeroth Law of Thermodynamics

Establishes the concept of temperature. If two systems are in thermal equilibrium with a third system, they are in thermal equilibrium with each other.

4. First Law of Thermodynamics

Expresses the principle of conservation of energy:

ΔQ = ΔU + W

• ΔQ: Heat supplied to the system.
• ΔU: Change in internal energy.
• W: Work done by the system.

5. Second Law of Thermodynamics

Describes the direction of natural processes and introduces the concept of entropy (S):

• Heat flows from a hot body to a cold body spontaneously.
• Kelvin-Planck and Clausius statements explain this principle in different forms.

6. Entropy

A measure of disorder or randomness in a system. For a reversible process:

ΔS = ΔQrev / T

7. Heat Engines and Refrigerators

• Heat Engine: Converts heat energy into work, operating in a cyclic process. Efficiency (η) is given by:η = Work output / Heat input
• Refrigerator: Transfers heat from a cold body to a hot body using external work. Its performance is measured by the coefficient of performance (COP).

8. Specific Heat Capacity and Calorimetry

• Specific Heat Capacity (c): The amount of heat required to raise the temperature of 1 kg of a substance by 1°C.
• Calorimetry: The study of heat transfer during physical or chemical changes.

Applications of Thermodynamics

Thermodynamics principles are widely used in engines, refrigerators, air conditioners, and power plants. It explains phenomena like melting, boiling, and phase transitions in everyday life.

This chapter forms the foundation for understanding advanced topics in physics, including statistical mechanics and thermodynamic cycles. It emphasizes energy conservation and the natural tendency of systems to evolve toward equilibrium.

Now, you can proceed to solve multiple-choice questions based on these concepts to strengthen your understanding.

Class 11 Physics Thermodynamics MCQ with Answers

1. Which of the following variables is a thermodynamic state variable?

(a) Work

(b) Heat

(c) Internal energy

(d) None of these

Answer: (c) Internal energy

Explanation: Internal energy is a property of the system that depends only on the state of the system, not on how it was reached. Work and heat depend on the process, so they are not state variables.

2. When steam is converted into water, the internal energy of the system:

(a) Increases

(b) Decreases

(c) Remains constant

(d) Becomes zero

Answer: (b) Decreases

Explanation: When steam (gas) condenses into water (liquid), energy is released to the surroundings, reducing the internal energy of the system.

3. Which of the following is NOT true about the isothermal expansion of an ideal gas?

(a) There is no change in internal energy

(b) Heat supplied to the gas is equal to work done

(c) The ideal gas equation for the process is PV/T = constant

(d) The ideal gas equation for the process is PV = constant

Answer: (c) The ideal gas equation for the process is PV/T = constant

Explanation: In isothermal processes, the temperature remains constant, so the correct relation is PV = constant, not PV/T = constant.

4. Which process allows the maximum work to be done on an ideal gas when compressed to half its initial volume?

(a) Isothermal

(b) Isochoric

(c) Isobaric

(d) Adiabatic

Answer: (d) Adiabatic

Explanation: In an adiabatic process, there is no heat exchange, so the work done is entirely due to the change in internal energy, making it greater than other processes under similar conditions.

5. The coefficient of performance (COP) of a refrigerator is 5. If the temperature inside the freezer is -20°C, calculate the heat rejected to the surroundings:

(a) 11°C

(b) 41°C

(c) 21°C

(d) 31°C

Answer: (d) 31°C

Explanation: The heat rejected to the surroundings is calculated using the COP formula. Since the COP is 5, the heat rejected is greater than the cooling effect, resulting in 31°C.

6. Select the incorrect statement:

(a) For the triple point of water, 1°K = 1/273.16.

(b) The first law of thermodynamics is also known as the law of thermal equilibrium.

(c) The triple point of water is a reference point on the thermodynamic temperature scale.

(d) At room temperature, the heat of combustion is not found.

Answer: (d) At room temperature, the heat of combustion is not found.

Explanation: Heat of combustion can be measured at room temperature, so the statement is incorrect. The other statements are true.

7. What condition is necessary for a reaction to be spontaneous at all temperatures?

(a) ΔH < ΔG

(b) ΔG and ΔH should be positive

(c) ΔH = ΔG = 0

(d) ΔG and ΔH should be negative

Answer: (d) ΔG and ΔH should be negative

Explanation: A reaction is spontaneous at all temperatures if both the enthalpy (ΔH) and Gibbs free energy (ΔG) are negative, indicating an energetically favorable process.

8. A gas is compressed to half of its initial volume. The work done is:

(a) Higher during isothermal compression

(b) Independent of the process used

(c) Higher during adiabatic compression

(d) Dependent on the type of gas

Answer: (c) Higher during adiabatic compression

Explanation: In an adiabatic process, no heat is exchanged, so all the work comes from the internal energy, leading to more work than in an isothermal process.

9. Which factor affects the heat of reaction according to Kirchhoff’s equation?

(a) Molecularity

(b) Temperature

(c) Pressure

(d) Volume

Answer: (b) Temperature

Explanation: Kirchhoff’s equation relates the heat of reaction to temperature changes, showing how it varies with temperature.

10. For all reactions, the nature of chemical dissociation is:

(a) Exothermic

(b) Reversible

(c) Endothermic

(d) Reversible and endothermic

Answer: (d) Reversible and endothermic

Explanation: Chemical dissociation involves breaking bonds, which requires energy (endothermic) and is typically a reversible process.

11. Which of the following is the largest unit of energy?

(a) Electron volt

(b) Joule

(c) Calorie

(d) Erg

Answer: (c) Calorie

Explanation: Among these units, a calorie represents the largest amount of energy. It is commonly used in food energy measurements.

Get NCERT Solutions for Class 11 Physics All Chapters

• Chapter 1: Physical World
• Chapter 2: Units and Measurements
• Chapter 3: Motion in a Straight Line
• Chapter 4: Motion in a Plane
• Chapter 5: Laws of Motion
• Chapter 6: Work, Energy, and Power
• Chapter 7: System of Particles and Rotational Motion
• Chapter 8: Gravitation
• Chapter 9: Mechanical Properties of Solids
• Chapter 10: Mechanical Properties of Fluids
• Chapter 11: Thermal Properties of Matter
• Chapter 12: Thermodynamics
• Chapter 13: Kinetic Theory
• Chapter 14: Oscillations
• Chapter 15: Waves

FAQs on Thermodynamics MCQ Class 11 Physics

How do I simplify complex MCQs involving multiple thermodynamic concepts?

To solve complex MCQs, break the problem into smaller parts. Start by identifying the type of process (isothermal, adiabatic, etc.), then apply the relevant laws step by step. If needed, draw a simple diagram like a PV or TS curve to visualize the process. Always check the units of given values, such as converting Celsius to Kelvin if required. Keywords like reversible, constant pressure, or adiabatic in the question will guide your calculations. Staying organized and systematic will make solving such questions easier.

How do I identify the type of thermodynamic process in a question?

To identify the type of thermodynamic process, check the conditions mentioned in the question. If the temperature is constant, it is an isothermal process. If no heat is exchanged, it is an adiabatic process. If the volume remains constant, it is an isochoric process, and if the pressure remains constant, it is an isobaric process. Understanding these basic clues will help you figure out the process and use the correct formula to solve the problem.