🔥 Kinetic Theory of Gases – Stage 3 (Page 1)

Advanced Objective Questions (JEE Advanced Level)

This stage focuses on tough, examiner-designed questions that require deep conceptual clarity, not formulas alone.

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🔹 Question 1 (Conceptual – Single Correct)

Two gases A and B have the same pressure and temperature. The molar mass of A is twice that of B. Which statement is correct?

• A) Average speed of A is twice that of B
• B) RMS speed of B is √2 times that of A
• C) Average kinetic energy of A is greater
• D) Number density of A is greater

Correct Answer: B

Reason:

• Speed ∝ 1/√M
• KE depends only on temperature

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🔹 Question 2 (Multi-Correct)

For an ideal gas at equilibrium, which of the following are true?

• A) Molecular speeds are uniformly distributed
• B) Average velocity of molecules is zero
• C) RMS speed depends on pressure
• D) Mean free path increases with decrease in pressure

Correct Answers: B, D

Key Logic:

• Velocities cancel vectorially
• Mean free path ∝ 1/pressure

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🔹 Question 3 (Integer Type)

If the temperature of a gas is increased by 300%, by what factor does its RMS speed increase?

Solution:

• T_final = 4T
• v_rms ∝ √T
• Increase factor = √4 = 2

Answer: 2

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🔹 Question 4 (Trap Question – Very Important)

All molecules of a gas are suddenly brought to rest. Which statement is true immediately after?

• A) Pressure becomes zero
• B) Temperature becomes zero
• C) Internal energy becomes zero
• D) Situation is physically impossible

Correct Answer: D

Explanation: Random motion cannot stop instantly without external work.

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🔹 Question 5 (Assertion–Reason)

Assertion (A): At a given temperature, lighter molecules move faster.

Reason (R): All molecules at same temperature have same kinetic energy.

Correct Option: Both A and R are true, and R explains A.

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🔹 Examiner Insight (Very Important)

• KTG questions are mostly logic-based
• Temperature = energy key
• Mass = speed key
• Pressure = collisions key

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✅ Stage 3 – Page 1 Completed Successfully

📚 IIT–JEE Physics Complete Library (Class XI)

Curated for IIT-JEE Advanced Aspirants
Concepts • Numericals • Objective Questions • Revision Capsules

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🔥 Kinetic Theory of Gases (KTG) – Complete Library

1. KTG – Part 1
2. KTG – Part 2
3. KTG – Part 3
4. KTG – Part 4
5. KTG – Part 5
6. KTG – Part 6
7. KTG – Part 7
8. KTG – Special Notes
9. KTG – Part 9
10. KTG – Part 10
11. KTG – Part 11
12. KTG – Part 12
13. KTG – Part 13
14. KTG – Part 14
15. KTG – Part 15
16. KTG – Part 16
17. KTG – Part 17
18. KTG – Part 18
19. KTG – Part 19
20. KTG – Part 20
21. KTG – Part 21
22. KTG – Part 22
23. KTG – Part 23
24. KTG – Part 24
25. KTG – Part 25
26. KTG – Part 26
27. KTG – Part 27
28. KTG – Part 28
29. KTG – Part 29
30. KTG – Part 30

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📐 Properties of Matter – Complete IIT-JEE Library

1. Properties – Part 1
2. Properties – Part 2
3. Properties – Part 3
4. Properties – Part 4
5. Properties – Part 5
6. Properties – Part 6
7. Properties – Part 7
8. Properties – Part 8
9. Properties – Part 9
10. Properties – Part 10
11. Properties – Part 11
12. Properties – Part 12
13. Properties – Part 13
14. Properties – Part 14
15. Properties – Part 15
16. Properties – Part 16
17. Properties – Part 17
18. Properties – Part 18
19. Properties – Part 19
20. Properties – Part 20
21. Properties – Part 21
22. Properties – Part 22
23. Properties – Part 23
24. Properties – Part 24
25. Properties – Part 25

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🌟 Master & Mega Physics Libraries

• IIT-JEE Physics Master Library
• Physics Complete Mega Library
• SHM Complete Library
• Waves – JEE Advanced Library
• Gravitation Library
• Momentum & Collisions Library
• Centre of Mass Library
• Work Energy Power Library

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