From first law of thermodynamics, ΔU=q+W In adiabatic expansion, q=0 ∴ΔU=W During expansion of a gas w is negative i.e w<0 or ΔU<0. We know that, ΔU=nCVΔT ∴∴nCVΔT<0TC−TA<0 or or ΔT<0TC<TA Thus, option (4) is incorrect while the remaining options are correct.
NEET UG 2019 — Chemistry Physical Chemistry
2019mcqhard
Reversible expansion of an ideal gas under isothermal and adiabatic conditions are as shown in the figure. 
AB→ Isothermal expansion AC→ Adiabatic expansion Which of the following option is not correct?
Official previous-year question
Held on 30 Apr 2019 · Verified 9 Jul 2026.
Options
- A
ΔSisothermal >ΔSadiabatic
- B
TA=TB
- C
Wisothermal >Wadiabatic
- D
Tc>TA
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