Q. Which of the following statements is true?
A) Internal energy of a gas depends only on the state of the gas
B) In an isothermal process change in internal energy is maximum
C) Area under pressure, volume graph equals heat supplied in any process
D) Work done is state dependent but not path dependent
Explanation
(a) In taking a system from one state to another by different processes, the heat transferred Q and work done W are different, but their difference Q-W is same for all processes. It gives the internal energy of the system.
$\mathrm{\Delta}U = Q - W$
Thus, internal energy U of a thermodynamic system is a characteristic property of the state of the system, it does not matter how that state has been obtained.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.