Q. When a gas expands adiabatically
A) No energy is required for expansion
B) Energy is required and it comes from the wall of the container of the gas
C) Internal energy of the gas is used in doing work
D) Law of conservation of energy does not hold
Explanation
(c) $\mathrm{\Delta}Q = \mathrm{\Delta}U + \mathrm{\Delta}W = 0 \Rightarrow \mathrm{\Delta}W = - \mathrm{\Delta}U$
If $\mathrm{\Delta}W$ is positive $i.e.,$ gas does work then $\mathrm{\Delta}U$ should be negative meaning internal energy is used in doing work
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.