🔥 Kinetic Theory of Gases – Stage 2 (Page 9)

This page trains you to combine formulas, avoid traps, and solve real JEE Advanced PYQ-style problems.

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1️⃣ PYQ Type: Same Temperature – Different Gases

Question: Two gases A and B at same temperature.

• Average kinetic energy?
• RMS speed?

Answer:

• ✔ Average KE → SAME (depends only on T)
• ✔ RMS speed → Different (depends on molar mass)

🔑 Examiner checks whether you separate energy concept from speed concept.

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2️⃣ PYQ Type: Pressure Ratio with Temperature Change

Given: Gas in rigid container, temperature doubles.

Pressure ∝ T (V constant)

Result: Pressure becomes 2 times

❌ Many students wrongly apply √T here (that is for speed).

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3️⃣ Mixed Concept: Speed + Collision

Question: If molecular speed increases, what happens?

• Collision frequency → increases
• Momentum transfer → increases
• Pressure → increases

⚠ But ONLY if volume is constant.

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4️⃣ PYQ Type: Mean Free Path Comparison

Mean free path (λ) depends on:

• Density
• Molecular diameter

At same pressure:

• Higher temperature → larger λ

✔ Temperature indirectly affects λ via density.

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5️⃣ Multi-Correct PYQ Logic

Statements:

1. All molecules have same speed ❌
2. All molecules have same KE ❌
3. Average KE depends on temperature ✔
4. Pressure arises from collisions ✔

🎯 Correct options often include BOTH microscopic + macroscopic logic.

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6️⃣ Integer-Type PYQ

Question: RMS speed ratio when temperature becomes 9T?

v ∝ √T → √9 = 3

Answer: 3

✔ Square root handling is critical.

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7️⃣ Concept Linking (KTG + Thermodynamics)

Average KE per molecule = (3/2)kT

• Links KTG with temperature definition
• Independent of gas type
• Independent of pressure

💡 This relation is a favorite base for tricky questions.

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8️⃣ Speed Ordering Trap

Most Probable < Average < RMS

Any option violating this order → eliminate instantly.

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9️⃣ JEE Advanced Strategy Tip

• Do not calculate unless required
• Compare ratios wherever possible
• Always check given constraints

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✅ Stage 2 – Page 9 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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📌 Updated regularly • Built for IIT-JEE Success