Q. Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : In an insulated container, a gas is adiabatically shrunk to half of its initial volume. The temperature of the gas decreases. Reason (R): Free expansion of an ideal gas is an irreversible and an adiabatic process. In the light of the above statements, choose the correct answer from the options given below :
A) Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
B) (A) is false but (R) is true
C) (A) is true but (R) is false
D) Both (A) and (R) are true and (R) is the correct explanation of (A)
Explanation
[Solution by Dr. Abubacker] In adiabatic compression, work is done on the gas, so its internal energy and temperature increase: (A) is false. Free expansion of an ideal gas (against vacuum, $Q=0$) is indeed irreversible and adiabatic: (R) is true. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.