🔥 Thermodynamics – Objective Questions

Set 4 : Extreme JEE Advanced / Olympiad Level

⚠️ Very High Difficulty
✔ Conceptual + Mathematical Traps
✔ Second Law & Entropy Dominant

Q3️⃣1️⃣

An engine operates between temperatures T₁ and T₂ (T₁ > T₂). If its efficiency is η, which condition must be satisfied?

• A) η ≤ 1 − T₂/T₁
• B) η = 1 − T₂/T₁ for all engines
• C) η depends on working substance
• D) η > Carnot efficiency possible

✔ Correct: A

---

Q3️⃣2️⃣

In a cyclic process shown on a PV diagram, the area enclosed represents:

• A) Heat absorbed
• B) Internal energy change
• C) Net work done
• D) Entropy change

✔ Correct: C

---

Q3️⃣3️⃣

A gas undergoes a process in which temperature remains constant but entropy increases. The process is:

• A) Reversible isothermal
• B) Irreversible isothermal
• C) Reversible adiabatic
• D) Free expansion

✔ Correct: B, D

---

Q3️⃣4️⃣

For a reversible process:

• A) Entropy of universe increases
• B) Entropy of universe decreases
• C) Entropy of universe remains constant
• D) Process must be slow

✔ Correct: C, D

---

Q3️⃣5️⃣

An ideal gas undergoes free expansion in vacuum. Which is true?

• A) ΔU = 0
• B) ΔT = 0
• C) ΔS > 0
• D) Work done is maximum

✔ Correct: A, B, C

---

Q3️⃣6️⃣

Two Carnot engines A and B operate between the same temperature limits. Which statement is correct?

• A) Efficiency of A > B
• B) Efficiency of B > A
• C) Both have same efficiency
• D) Efficiency depends on working gas

✔ Correct: C

---

Q3️⃣7️⃣

Entropy change of universe is minimum for:

• A) Reversible process
• B) Irreversible process
• C) Free expansion
• D) Spontaneous process

✔ Correct: A

---

Q3️⃣8️⃣

Which of the following violates the second law of thermodynamics?

• A) Refrigerator working without input work
• B) Heat engine with 100% efficiency
• C) Heat flowing from cold to hot spontaneously
• D) Carnot engine

✔ Correct: A, B, C

---

Q3️⃣9️⃣

For an adiabatic irreversible process:

• A) ΔQ = 0
• B) ΔS > 0
• C) ΔU = −W
• D) Process is isentropic

✔ Correct: A, B, C

---

Q4️⃣0️⃣

A system returns to its initial state after a cycle. Then:

• A) Net heat absorbed = net work done
• B) Change in internal energy = 0
• C) Entropy of system = 0
• D) Entropy of universe = 0

✔ Correct: A, B

---

✅ Objective Set – Page 4 Completed
➡ Next: Page 5 – Mixed Numerical + Assertion–Reason (JEE Advanced)

📚 IIT–JEE PHYSICS MASTER LIBRARY (ADVANCED)

One-stop structured learning hub for JEE Advanced Physics
Concepts • Objective Questions • Final Revision • Complete Libraries

---

🔥 Thermodynamics – Objective Final Revision

Thermodynamics – Set 1
Set 2
Set 3
Set 4
Set 5
Set 6
Set 7
Set 8
Set 9
Set 10
Set 11
Set 12
Set 13
Set 14
Set 15
Set 16
Set 17
Set 18
Set 19
Set 20
Set 21
Set 22
Set 23
Set 24
Set 25
Set 26
Set 27
Set 28
Set 29
Set 30
Set 31
Set 32
Set 33
Set 34
Set 35
Set 36
Set 37
Set 38
Set 39
Set 40
Set 41
Set 42
Set 43
Set 44
Set 45
Set 46
Set 47
Set 48
Set 49
Set 50
Set 51
Set 52
Set 53
Set 54
Set 55
Set 56
Set 57
Set 59

---

📘 Complete Physics Libraries

• SHM – Complete Library
• Waves – Objective Library
• Gravitation – Complete Library
• Momentum & Collisions
• Centre of Mass
• Work, Energy & Power
• WEP – Intermediate Notes
• Motion in a Plane

---

🔗 Learning Hubs & Community

• IIT–JEE Physics Master Library
• Physics Mega Library
• Advanced Stage-5 Material
• Shaktimatha Learning Resource Hub
• WhatsApp Learning Channel

---

© Mind Grow Magazine | Structured for Serious IIT–JEE Aspirants