STAGE C – Page 6

Thermodynamics: Final Exam-Day Capsule

Read this once before entering the exam hall

⚠️ FIRST 30 SECONDS – MENTAL SETUP

• Thermodynamics = logic + laws
• Never rush into formulas
• Identify process → law → sign → shortcut

📌 ABSOLUTE MUST-REMEMBER FACTS

• ΔU depends only on temperature
• Work depends on path
• Heat is NOT a state variable
• Entropy of universe never decreases

🔥 PROCESS QUICK IDENTIFICATION

• Isothermal: ΔU = 0 → Q = W
• Adiabatic: Q = 0 → ΔU = –W
• Isochoric: W = 0 → Q = ΔU
• Isobaric: W = PΔV

📈 GRAPH POWER RULES

• Area under PV curve = Work
• Steeper PV curve → Less work
• TS graph area = Heat absorbed
• Same endpoints ≠ same work

⚙️ ENGINE & REFRIGERATOR FINAL LOGIC

• Efficiency depends only on reservoirs
• Carnot is maximum possible efficiency
• No real engine reaches Carnot
• COP can exceed 1 (normal)

🚫 MOST COMMON IIT TRAPS

• Assuming ΔU ≠ 0 in isothermal process
• Mixing COP and efficiency
• Wrong sign of work during compression
• Ignoring irreversibility

🧠 SMART ELIMINATION TECHNIQUES

• Check physical possibility first
• Reject negative absolute temperature answers
• Entropy decrease of universe → impossible
• Efficiency > Carnot → reject instantly

⏱️ TIME-SAVING SHORTCUTS

• Use ratios instead of values
• Cancel R, γ early
• Avoid numerical substitution till last step
• Predict trend before solving

🧪 CONCEPTUAL YES / NO TEST

• Is heat flowing without temperature difference? → NO
• Is 100% efficient engine possible? → NO
• Can entropy of system decrease? → YES
• Can entropy of universe decrease? → NEVER

✅ FINAL 10-SECOND CHECK BEFORE MARKING ANSWER

• Sign convention correct?
• Law violated?
• Units sensible?
• Physical meaning exists?

If all YES → lock the answer.

📚 IIT–JEE PHYSICS MASTER LIBRARY (ADVANCED)

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

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🔥 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

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📘 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

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🔗 Learning Hubs & Community

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

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