NEETPhysicsThermodynamics
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In an isobaric expansion of an ideal gas, the heat supplied to the gas is always less than the work done by the gas. Reason (R): During an isobaric expansion, the temperature of the ideal gas increases, leading to an increase in its internal energy. In the light of the above statements, choose the
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
- BBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- C(A) is correct but (R) is not correct
- D(A) is not correct but (R) is correct
Correct answer
D. (A) is not correct but (R) is correct
Step-by-step solution
In an isobaric process, pressure is constant. For an ideal gas, V T at constant pressure. During expansion, volume increases, so temperature must increase. This leads to an increase in internal energy ( U > 0 ). Thus, the Reason is correct. According to the first law of thermodynamics, Q = W + U . Since U is positive during an isobaric expansion, the heat supplied ( Q ) must be greater than the work done ( W ). The Assertion states that heat supplied is less than work done, which is incorrect. Therefore, (A) is not