NEET levelSingle correct optionDifficulty 1 of 3td059
One mole of an ideal gas is compressed isothermally and reversibly. Which statement is correct?
ANo heat is exchanged because the process is reversible
BThe internal energy of the gas increases by the amount of work done on it
CThe temperature of the gas rises
DThe gas releases heat to the surroundings equal in magnitude to the work done on it
Answer: D
For an ideal gas at constant T, ΔU=0, so q=−w. Work is done on the gas (w>0), therefore q<0: an equal amount of heat flows out to the surroundings. Reversibility does not imply q=0; that condition belongs to adiabatic processes.