Last Updated on June 5, 2025 by XAM CONTENT
Mastering the important concepts in Class 11 Physics Chapter 12 – Kinetic Theory is essential for scoring high marks in your exams. That’s why we’ve put together chapterwise multiple-choice questions (MCQs) with answers to help you revise effectively and boost your confidence. It is a part of MCQ Questions for CBSE Class 11 Physics Series.
These multiple-choice questions will help you assess your knowledge, improve accuracy, and boost confidence for your exams. Whether you are preparing for school tests, online tests or competitive exams, these Kinetic Theory MCQs will strengthen your conceptual clarity.
| Chapter | Kinetic Theory |
| Book | Physics for Class 11 |
| Type of Questions | MCQ Questions |
| Nature of Questions | Competency Based Questions |
| Board | CBSE |
| Class | 11 |
| Subject | Physics |
| Useful for | Class 11 Studying Students |
| Answers provided | Yes |
| Difficulty level | Mentioned |
| Important Link | Class 11 Physics Chapterwise MCQ Questions |
MCQ Questions on Kinetic Theory Class 11 Physics (PDF Download)
MCQs
Q1. The pressure of an ideal gas is given by:
(a) nRT
(b) (1/3)nm<v²>
(c) kT/v
(d) (2/3)nmv
Show Answer
Answer: (b)
Explanation: According to kinetic theory, P = (1/3)nm<v²> where n = number density and v² = mean square speed.
Q2. The average kinetic energy of a molecule of an ideal gas is directly proportional to:
(a) Pressure
(b) Volume
(c) Temperature
(d) Density
Show Answer
Answer: (c)
Explanation: Average KE per molecule = (3/2)kT, hence it depends only on temperature.
Q3. Which of the following correctly represents the root mean square (rms) speed of gas molecules?
(a) √(kT)
(b) √(3kT/m)
(c) √(3kT)
(d) √(T/k)
Show Answer
Answer: (b)
Explanation: v_rms = √(3kT/m), where k is Boltzmann constant, T is temperature, and m is molecular mass.
Q4. A real gas behaves like an ideal gas at:
(a) High pressure, low temperature
(b) High pressure, high temperature
(c) Low pressure, high temperature
(d) Low pressure, low temperature
Show Answer
Answer: (c)
Explanation: At low pressure and high temperature, intermolecular forces are negligible, so real gases behave ideally.
Q5. In the kinetic theory, pressure is interpreted as:
(a) Elastic collisions between molecules
(b) Change in volume
(c) Momentum transfer per unit area per second
(d) Heat transfer by molecules
Show Answer
Answer: (c)
Explanation: Pressure arises from momentum transfer due to collisions with container walls.
Q6. The ideal gas law fails at low temperatures because:
(a) Intermolecular attractions increase
(b) Collisions become inelastic
(c) Volume becomes negligible
(d) Heat capacity decreases
Show Answer
Answer: (a)
Explanation: At low temperature, intermolecular attractions become significant and ideal gas assumptions break.
Q7. The concept of mean free path is based on:
(a) Number of atoms
(b) Average velocity
(c) Frequency of collisions
(d) Molecular volume
Show Answer
Answer: (c)
Explanation: Mean free path is inversely related to collision frequency: λ = v/ν.
Q8. Which law provides the basis for temperature measurement in thermodynamics?
(a) First law
(b) Second law
(c) Zeroth law
(d) Third law
Show Answer
Answer: (c)
Explanation: Zeroth law establishes thermal equilibrium and hence defines temperature.
Q9. The value of Boltzmann constant k is:
(a) 1.38 × 10⁻²³ J/K
(b) 8.31 J/mol-K
(c) 9.8 m/s²
(d) 6.02 × 10²³
Show Answer
Answer: (a)
Explanation: k = 1.38 × 10⁻²³ J/K is a fundamental constant relating temperature and energy.
Q10. Equipartition theorem assigns how much energy to each translational degree of freedom?
(a) kT
(b) 2kT
(c) (1/2)kT
(d) 3kT
Show Answer
Answer: (c)
Explanation: Each degree of freedom gets (1/2)kT of energy on average.
Q11. Which of the following molecules would have the highest rms speed at the same temperature?
(a) O₂
(b) N₂
(c) H₂
(d) CO₂
Show Answer
Answer: (c)
Explanation: Lighter gases have higher rms speeds; H₂ has the lowest molar mass.
Q12. A gas is compressed adiabatically. What happens to its temperature?
(a) Increases
(b) Decreases
(c) Remains same
(d) Becomes zero
Show Answer
Answer: (a)
Explanation: In adiabatic compression, work is done on the gas, increasing its internal energy and temperature.
Q13. Which expression gives the mean free path λ of gas molecules?
(a) 1/nσ
(b) 1/n²d²
(c) 1/√(nπd²)
(d) 1/(√2 n π d²)
Show Answer
Answer: (d)
Explanation: λ = 1/(√2 n π d²) where n is number density and d is molecular diameter.
Q14. In the kinetic theory, what does temperature not depend on?
(a) Molecular mass
(b) Average kinetic energy
(c) Boltzmann constant
(d) None of these
Show Answer
Answer: (a)
Explanation: Temperature relates to average kinetic energy, not molecular mass.
Q15. Which of the following increases with temperature for an ideal gas?
(a) Mass
(b) Average molecular speed
(c) Density
(d) Number of molecules
Show Answer
Answer: (b)
Explanation: rms speed v ∝ √T; thus speed increases with temperature.
Q16. The law of equipartition of energy fails at:
(a) High temperature
(b) Low pressure
(c) Low temperature
(d) High pressure
Show Answer
Answer: (c)
Explanation: At low temperature, quantum effects dominate and the law may not hold.
Q17. Which mode of energy contributes twice the energy per degree of freedom?
(a) Translational
(b) Rotational
(c) Vibrational
(d) Potential
Show Answer
Answer: (c)
Explanation: Vibrational mode has both kinetic and potential energy, contributing kT.
Q18. A diatomic gas molecule at room temperature has how many degrees of freedom?
(a) 2
(b) 3
(c) 5
(d) 6
Show Answer
Answer: (c)
Explanation: It has 3 translational + 2 rotational degrees at room temperature.
Q19. Which of the following is true for ideal gases?
(a) They obey Boyle’s law only
(b) They obey Charles’ law only
(c) They obey both Boyle’s and Charles’ laws
(d) They obey neither
Show Answer
Answer: (c)
Explanation: Ideal gases follow both Boyle’s and Charles’ laws.
Q20. The internal energy of an ideal gas is a function of:
(a) Pressure only
(b) Volume only
(c) Temperature only
(d) Temperature and pressure
Show Answer
Answer: (c)
Explanation: For ideal gases, internal energy depends only on temperature.
We hope the given mcq questions with Answers for Kinetic Theory Class 11 helps you in your learning.
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Topics from which mcq questions may be asked
- Molecular theory of gases
- Pressure and kinetic energy
- Gas laws
The kinetic theory connects microscopic motion with macroscopic properties.
Frequently Asked Questions (FAQs) on Kinetic Theory MCQ Questions
Q1: What is the best way to prepare for Class 11 Physics MCQ questions?
A1: The best way is to study NCERT concepts thoroughly, practice topicwise MCQs regularly, and focus on understanding fundamental principles rather than rote learning. Solving previous year MCQs and mock tests can boost accuracy and speed.
Q2: Are NCERT questions enough for Class 11 Physics MCQ-based exams?
A2: NCERT forms the base for all CBSE Physics MCQs. However, for better preparation, students should solve additional MCQs from reference books and practice HOTS and competency-based questions to develop deeper conceptual clarity.
Q3: Where can I find chapterwise Class 11 Physics MCQ questions with answers?
A3: You can find chapterwise MCQ questions with answers and detailed explanations on trusted educational platforms like xamcontent.com and physicsgurukul.com. These cover both basic and advanced-level questions.
Q4: Do CBSE Class 11 exams include MCQs?
A4: Yes, as per the latest CBSE exam pattern, objective questions, including MCQs, are part of the final exam paper. MCQs test conceptual understanding and application skills.
Q5: How to score high in Class 11 Physics MCQs?
A5: To score high, understand the theory from NCERT, solve a variety of MCQs (basic, conceptual, numerical), and regularly revise formulas and diagrams. Avoid guesswork and focus on time management during tests.
Q6: What are competency-based MCQs in Class 11 Physics?
A6: Competency-based MCQs assess a student’s ability to apply concepts in real-life or unfamiliar scenarios. These questions go beyond textbook definitions and require logical reasoning and application of physics principles.
