Which of the following relations are correct? (A) U = q + p V (B) G = H - T S (C) S = qrevT (D) H = U - nRT
Thermodynamics · Class 11 · JEE Main Previous Year Question
Which of the following relations are correct? (A) (B) (C) (D)
- a
C and D only
- b✓
B and C only
- c
A and B only
- d
B and D only
B and C only
🧠 Two relations have wrong signs — spot them Check each against the standard thermodynamic identities.
(A) — Wrong. First Law at constant pressure: (work done by system carries a minus sign). (A) has the sign flipped.
(B) — Correct. ✓
(C) — Correct. ✓
(D) — Wrong. Correct form is . (D) has a minus where it should be plus.
Only B and C are correct → option (b).
⚠️ Relation (D) has a sign flip that many students miss — it's , not .
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