Three moles on an ideal mono-atomic gas perform a cycle shown in figure. The gas temperature at different states are $T_1 = 400 k, T_2 = 2400 k and T_4 = 1200 k.$ Heat supplied to the gas is
 

As 1-2 and 3-4 processes are isochoric,   $V_1=V_{2}and{V}_3=V_4$

$\begin{array}{l}\frac{T_3}{T_2}=\frac{V_3}{V_2}=\frac{V_4}{V_1}=\frac{T_4}{T_1}\\ \Rightarrow T_3=\frac{T_2.T_4}{T_1}=\frac{2400\times 1200}{400}k=7200k\\ \therefore Q_1=Heat\sup plied=3.\frac{3R}{2}.\left(2400-400\right)+3.\frac{5R}{2}.\left(7200-2400\right)\\ Q_1=9000R+360,00R=45000R\end{array}$