If Q is the amount of heat supplied to 'n' moles of a rigid diatomic gas at constant pressure, U is the change in internal energy and W is the work done then W : U : Q is

Step-by-step solution

For a rigid diatomic gas, the number of degrees of freedom is f = 5 . The molar heat capacity at constant volume is C_v = 5 2 R and at constant pressure is C_p = C_v + R = 7 2 R . The heat supplied at constant pressure is Q = nC_p T = n ( 7 2 R ) T . The change in internal energy is U = nC_v T = n ( 5 2 R ) T . The work done by the gas at constant pressure is W = nR T . The required ratio is W : U : Q = nR T : 5 2 nR T : 7 2 nR T . W : U : Q = 1 : 5 2 : 7 2 = 2 : 5 : 7 . Answer: 2:5:7