Two cylinders A and B fitted with pistons, contain equal number of moles of an ideal monoatomic gas at 400 K. The piston of a is free move while that of B is held fixed. Same amount of heat energy is given to the gas in each cylinder. If the rise in temperature of the gas in A is 42 K. the rise in temperature of the gas in B is $(\gamma=5/3)$

Question

\[\begin {array} {1 1} (a)\;25.2\;K & \quad (b)\;35\;K \\ (c)\;42\;K & \quad (d)\;70\;K \end {array}\]