Q. Starting with the same initial conditions, an ideal gas expands from volume $V_{1}$ to $V_{2}$ in three different ways. The work done by the gas is $W_{1}$ if the process is purely isothermal, $W_{2}$ if purely isobaric and $W_{3}$ if purely adiabatic. Then
A) $W_{2} > W_{1} > W_{3}$
B) $W_{2} > W_{3} > W_{1}$
C) $W_{1} > W_{2} > W_{3}$
D) $W_{1} > W_{3} > W_{2}$
Explanation
(a) The $p - V$ graphs three given processes are shown in figure
[image:12_image58.emf]
As work done by the gas = area under the $p - V$ graph (between the graph of $V$ axis) and
$(Area)_{2} > (Area)_{1} > (Area)_{3}\ \ \therefore W_{2} > W_{1} > W_{3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.