Given below are two statements:
Statement I: If heat is added to a system, its temperature must increase.
Statement II: If positive work is done by a system in a thermodynamic process, its volume must increase.
Options:
Both Statement I and Statement II are true
Both Statement I and Statement II are false
Statement I is true but Statement II is false
Statement I is false but Statement II is true
Correct answer:D
Standard Method
Given: Two statements about heat, temperature, and work done by a system in thermodynamics.
Find: Which option correctly identifies the truth values of Statement I and Statement II.
For Statement I, heat added to a system does not always increase temperature. In processes such as phase change or an isothermal process, heat may be supplied without any rise in temperature.
For example, during melting of ice or boiling of water, heat is added but the temperature remains constant. Therefore, Statement I is false.
For Statement II, the solution uses the relation
Under constant pressure, positive work done by the system implies
so the volume increases. Therefore, Statement II is true.
Hence, Statement I is false but Statement II is true. The correct option is D.
Assuming that adding heat always raises temperature. This is incorrect because during phase changes or isothermal processes, heat can change internal state without increasing temperature. Always check the nature of the thermodynamic process first.
Treating work done by the system as positive in every sign convention without relating it to expansion. In the convention used here, positive work by the system corresponds to expansion, so volume increases. Always confirm the sign convention and the physical meaning of the work term.
Get unlimited AI-adaptive practice, mastery tracking, and an AI tutor that explains every step — free to start.
