Question

Reversible expansion of an ideal gas under isothermal and adiabatic conditions are as shown in the figure.
AB $\rightarrow$ Isothermal expansion
AC $\rightarrow$ Adiabatic expansion
Which of the following options is not correct ?

• A. $\Delta S_{\text{isothermal}} > \Delta S_{\text{adiabatic}}$
• B. $T_A = TB$
• C. $W_{\text{isothermal}} > W_{\text{adiabatic}}$
• D. $T_c > TA$

Answer 1

Answer: (D)

In adiabatic expansion cooling effect will take place, $T_C$ will be less then $T_A$.
in adiabatic expansion $q = 0$
$\Delta U = w$
$Wpv < 0$
$\Delta U < 0$
$nC_{vm} \Delta T < 0$
$\Delta T < 0$
$T_C - T_A < 0$
$T_C < T_A$