Q. In changing the state of thermodynamics from $A$ to $B$ state, the heat required is $Q$ and the work done by the system is W. The change in its internal energy is
A) $Q + W$
B) $Q - W$
C) $Q$
D) $\frac{Q - W}{2}$
Explanation
(b) $\mathrm{\Delta}Q = \mathrm{\Delta}U + \mathrm{\Delta}W$
$\Rightarrow \ \mathrm{\Delta}U = \mathrm{\Delta}Q - \mathrm{\Delta}W = Q - W$ [using proper sign]
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.