(a)[2]
State the meaning of the internal energy of a system.
(b(i))[2]
State the total change in internal energy of the gas over the full cycle $P \to Q \to R \to P$. Explain your answer.
(b(ii))[5]
On Fig. 2.2, fill in the energy changes for the gas for (1) $P \to Q$, (2) $Q \to R$, and (3) $R \to P$.
(i)[2]
State the total change in internal energy of the gas for the complete cycle PQR P. Explain your answer.
(ii)[5]
On Fig. 2.2, fill in the energy changes for the gas for (1) $P \rightarrow Q$, (2) $Q \rightarrow R$, and (3) $R \rightarrow P$.