🔹 Kinetic Theory of Gases – Stage 1 (Page 1)

1️⃣ What is Kinetic Theory of Gases?

Kinetic Theory of Gases explains the macroscopic properties of gases (pressure, temperature, volume) in terms of the microscopic motion of gas molecules.

👉 It connects Thermodynamics with Newtonian Mechanics.

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2️⃣ Basic Assumptions of Kinetic Theory

• Gas consists of a very large number of identical molecules.
• Size of each molecule is negligible compared to distance between them.
• Molecules are in continuous, random motion.
• Collisions between molecules and container walls are perfectly elastic.
• No intermolecular force except during collision.
• Time of collision is negligible compared to time between collisions.

⚠️ JEE Insight: Any deviation from these assumptions → Real Gases.

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3️⃣ Concept of Ideal Gas

A gas that obeys all assumptions of kinetic theory and follows:

PV = nRT

• P → Pressure
• V → Volume
• n → Number of moles
• R → Universal gas constant
• T → Absolute temperature (Kelvin)

👉 Ideal gas is a theoretical model, but works well at:

• Low pressure
• High temperature

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4️⃣ Microscopic Meaning of Pressure

Gas pressure arises due to repeated collisions of molecules with the walls of the container.

Each collision transfers momentum to the wall → force → pressure.

Pressure ∝ Rate of change of momentum

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5️⃣ Molecular Speed – Important Idea

Gas molecules do not move with the same speed.

• Some move slow
• Some move fast
• Most move near an average value

This leads to the concept of speed distribution (Maxwell later).

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6️⃣ Temperature – Microscopic Interpretation

Temperature of a gas is a measure of the average kinetic energy of its molecules.

Average Kinetic Energy ∝ Absolute Temperature (T)

👉 Higher T → faster molecules → higher pressure (if volume fixed).

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📌 Key Takeaways (Exam Ready)

• KTG links mechanics + thermodynamics
• Pressure comes from molecular collisions
• Temperature measures average KE
• Ideal gas is an approximation

✔ Stage 1 – Page 1 COMPLETE

📚 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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