One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure. The change in internal energy of the gas during the transition is

One mole of an ideal diatomic gas undergoes a transition from A to B a

1.	One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure. The change in internal energy of the gas during the transition is
Answer» 20 J `-12 kJ` 20 kJ `-20 kJ` Solution :We know, `DELTA U = nC_(V)Delta T` `= n((5R)/(2))(T_(B) - T_(A))` [for diatomic gas, `C_(V) = (5R)/(2)`] `= (5nR)/(2) ((P_(B)V_(B))/(nR) - (P_(A)V_(A))/(nR)) [because PV = nRT]` `= (5)/(2) (P_(B)V_(B) - P_(A)V_(A)) = (5)/(2)(2 xx 10^(3) xx 6 - 5 xx 10^(3) xx 4) = -20 kJ`