1 mole of an ideal gas A (C_(v,m)=3R) and 2 mole of an ideal gas B are (C_(v.m)= (3)/(2)R) taken in a constainer and expanded reversible and adiabatically from 1 litre of 4 litre starting from initial temperature of 320K. DeltaE or DeltaU for the process is (in Cal) (Give your answer after divide with 240)

1 mole of an ideal gas A (C_(v,m)=3R) and 2 mole of an ideal gas B are

1.	1 mole of an ideal gas A (C_(v,m)=3R) and 2 mole of an ideal gas B are (C_(v.m)= (3)/(2)R) taken in a constainer and expanded reversible and adiabatically from 1 litre of 4 litre starting from initial temperature of 320K. DeltaE or DeltaU for the process is (in Cal) (Give your answer after divide with 240)
Answer» `-240R` 240R `-1920` Cal `-960R` Solution :`C_(V_("avg")) = (1 xx 3R + 2 xx (3)/(2) R)/(1 +2) = 2R rArr gamma = 3//2` `T_(1) V_(1)^(gamma-1) = T_(2) V_(2)^(gamma-1)` `320 xx (1)^(1//2) = T_(2) (4)^(1//2) rArr T_(2) = (320)/(2) = 160K` `Delta U= nC_(v) Delta T= 3 xx 2R xx (160-320)` `= -960 R = - 1920` cal