The work done in adiabatic compression of `2` mole of an ideal monoatomic gas by constant external pressure of `2 atm` starting from initial pressure of `1 atm` and initial temperature of `30 K(R=2 cal//"mol-degree")`

Answer

B

Explanation

`w=DeltaU=n underset(T_(1))overset(T_(2))intC_(vm)dT`
`w=2xx(R )/(gamma-1)(T_(2)-T_(1))`
`(T_(2)-T_(1))/(gamma-1)=-P_("ext")((T_(2))/(P_(2))-(T_(1))/(P_(1)))`
`(T_(2)-300)/((5)/(3)-1)=-2((T_(2))/(2)-(300)/(1))`
`1.5 T_(2)-450 =-T_(2)+600implies T_(2)=420 K`
`w=2xx(2)/((5)/(3)-1)(420-300)=720`