Q. Three moles of an ideal gas expanded spontaneously into vacuum. The work done will be
A) Infinite
B) 3 Joules
C) 9 Joules
D) Zero
Explanation
[Solution from source] Work in expansion is w = −p(ext)ΔV, and for free expansion into vacuum p(ext) = 0, so no work is done whatever the number of moles. Values like 3 J or 9 J wrongly link the work to the amount of gas. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.