🔥 Kinetic Theory of Gases – Stage 3 (Page 3)
Ultra-Advanced Problems (JEE Advanced Level)
This page tests deep microscopic understanding. Memorization completely fails here.
🔹 Question 1 (Very High Yield – Energy Distribution)
At temperature T, which fraction of molecules have kinetic energy greater than average kinetic energy?
- A) Less than 50%
- B) Exactly 50%
- C) More than 50%
- D) Cannot be determined
Correct Answer: A
Insight:
Maxwell distribution is skewed.
Most molecules lie below average energy.
🔹 Question 2 (Conceptual – Momentum Transfer)
Pressure exerted by a gas is mainly due to:
- A) Force of attraction between molecules
- B) Elastic collisions with walls
- C) Continuous force on walls
- D) Internal energy of gas
Correct Answer: B
Trap: Pressure arises from impulse, not force.
🔹 Question 3 (Numerical Logic – Mean Free Path)
If molecular diameter is doubled and pressure is halved, mean free path changes by what factor?
Solution:
- Mean free path ∝ 1 / (pressure × diameter²)
- Diameter² → 4 times
- Pressure → 1/2
Net effect = 1 / ( (1/2) × 4 ) = 1/2
Answer: Decreases by factor 2
🔹 Question 4 (Assertion–Reason – Classic IIT)
Assertion (A): At very low pressure, gas deviates from ideal behavior.
Reason (R): Volume of molecules becomes comparable to container volume.
Correct Option: A is false, R is false
Correct Concept:
Deviation occurs at high pressure, not low.
🔹 Question 5 (Tricky – RMS Speed)
Two gases have same temperature. Which quantity must be same?
- A) RMS speed
- B) Average speed
- C) Most probable speed
- D) Average kinetic energy
Correct Answer: D
Why?
Average KE = (3/2)kT → depends only on temperature.
🔹 Question 6 (Hard – Collision Count)
If the temperature of a gas is increased, number of collisions per second:
- A) Always increases
- B) Always decreases
- C) Remains same
- D) May increase or decrease
Correct Answer: D
Explanation:
Speed ↑ → collisions ↑
But number density ↓ (if pressure constant)
🧠 IIT Examiner’s Favorite Misconception
- Speed ≠ Energy
- Pressure ≠ Force
- Temperature ≠ Motion of one molecule
✅ Stage 3 – Page 3 Completed
📚 IIT–JEE Physics Complete Library (Class XI)
Curated for IIT-JEE Advanced Aspirants
Concepts • Numericals • Objective Questions • Revision Capsules
🔥 Kinetic Theory of Gases (KTG) – Complete Library
- KTG – Part 1
- KTG – Part 2
- KTG – Part 3
- KTG – Part 4
- KTG – Part 5
- KTG – Part 6
- KTG – Part 7
- KTG – Special Notes
- KTG – Part 9
- KTG – Part 10
- KTG – Part 11
- KTG – Part 12
- KTG – Part 13
- KTG – Part 14
- KTG – Part 15
- KTG – Part 16
- KTG – Part 17
- KTG – Part 18
- KTG – Part 19
- KTG – Part 20
- KTG – Part 21
- KTG – Part 22
- KTG – Part 23
- KTG – Part 24
- KTG – Part 25
- KTG – Part 26
- KTG – Part 27
- KTG – Part 28
- KTG – Part 29
- KTG – Part 30
📐 Properties of Matter – Complete IIT-JEE Library
- Properties – Part 1
- Properties – Part 2
- Properties – Part 3
- Properties – Part 4
- Properties – Part 5
- Properties – Part 6
- Properties – Part 7
- Properties – Part 8
- Properties – Part 9
- Properties – Part 10
- Properties – Part 11
- Properties – Part 12
- Properties – Part 13
- Properties – Part 14
- Properties – Part 15
- Properties – Part 16
- Properties – Part 17
- Properties – Part 18
- Properties – Part 19
- Properties – Part 20
- Properties – Part 21
- Properties – Part 22
- Properties – Part 23
- Properties – Part 24
- Properties – Part 25
🌟 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
No comments:
Post a Comment