A gas inside a cylinder receives thermal energy $q$. As it expands at constant pressure $p$, the gas performs useful work as its volume changes from $V_0$ to $V_F$, as illustrated. Which expression gives the efficiency of this change?
- A$\frac{pV_0}{q}$
- B$\frac{V_F}{V_0 q}$
- C$\frac{p(V_F - V_0)}{q}$
- D$\frac{(V_F - V_0)}{V_0 q}$