Question

The correct option for free expansion of an ideal gas under adiabatic condition is

• A. $q=0,\Delta T=0$ and $w=0$
• B. $q=0,\Delta T<0$ and $w>0$
• C. $q<0,\Delta T=0$ and $w=0$
• D. $q>0,\Delta T>0$ and $w>0$

Answer 1

The correct option is A $q=0,\Delta T=0$ and $w=0$

For free expansion of an ideal gas, $P_{ex}=0,$
$w=-P_{ex}\Delta V=0$
For adiabatic process,
$q=0$
According to first law of thermodynamics,
$\Delta U=q+w=0$

As internal energy of an ideal gas is a function of temperature,$\Delta U=0,\therefore \Delta T=0$
Option (a) is correct