
As the initial and final states in the three processes are same. Therefore,
$\Delta {u_1} = \Delta {u_2} = \Delta {u_3}$
Workdone, $W=Area\,under\,P-V\,graph$
As area under curve $1>$ area under curve $2>$ area under curve $3$
$\therefore {W_1} > {W_2} > {W_3}$
According to first law of thermodynamics,
$Q = W + \Delta u$
$As{W_1} > {W_2} > {W_3}\,and\,\Delta {u_1} = \Delta {u_2} = \Delta {u_3}$
$\therefore {Q_1} > {Q_2} > {Q_3}$

