Four grams of gas, confined to a cylinder, is carried through the cycle shown in Fig. 20-6. At $A$ the temperature of the gas is 400 ${ }^{\circ} \mathrm{C} .(a)$ What is its temperature at $B$ ? $(b)$ If, in the portion from $A$ to $B$, $2.20$ kcal flows into the gas, what is $c_{v}$ for the gas? Give your answers to two significant figures.