Question

An ideal gas is taken from point A to point C on P-V diagram through two process AOC and ABC as shown in the figure . Process AOC is isothermic

• A. Process AOC requires more heat than process ABC
• B. Process ABC requires more heat than process AOC
• C. Both process AOC & ABC require same amount of heat
• D. Data is insufficient for comparison of heat requirement for the two processes

Answer 1

The correct option is A Process AOC requires more heat than process ABC

Being a state-function, change in in internal energy($\Delta U$) is the same for the two processes AOC and ABC, i.e. $\Delta U_{AOC}=\Delta U_{ABC}$
Work done=W= area under P-V diagram
Hence $W_{AOC}>W_{ABC}$
$\Rightarrow \Delta U_{AOC}+W_{AOC}>\Delta U_{ABC}+W_{ABC}$
$\Rightarrow \Delta Q_{AOC}>\Delta Q_{ABC}$