Question

The reversible expansion of an ideal gas under adiabatic and isothermal conditions is shown in the figure. Which of the following statement(s) is (are) correct?

• A. $T_1=T_2$
• B. $T_3>T_1$
• C. $W_{\text{isothermal}}>W_{\text{adiabatic}}$
• D. $\Delta U_{\text{isothemal}}>\Delta U_{\text{adibatic}}$

Answer 1

Answer: (A), (C), (D)

The correct options are
A $T_1=T_2$
C $W_{\text{isothermal}}>W_{\text{adiabatic}}$
D $\Delta U_{\text{isothemal}}>\Delta U_{\text{adibatic}}$

(1) It is an Isothermal process and hence, $T_1=T_2$
(2) For an adiabatic expansion, temperature is decreased Hence $T_3<T_1$
(3) Work done in isothermal expansion is greater than adiabatic expansion due to temperature loss in adiabatic expansion.
(4) $(\Delta U{)}_{\text{isothermal}}=0$
$(\Delta U{)}_{\text{adiabatic}}=$ negative