Correct Answer - 4
As here volume of gas remains constant,
`(Delta Q)_(v) = mu C_(V) Delta T`, Here `C_(V) = 5 cal//mol K`
and `Delta T = (400 - 300) = 100 K`
and so for ideal gas `PV = mu RT`,
`mu = ((10)^(5) xx (0.2))/(8.31 xx 300) = 8 mol`
`(Delta Q)_(V) = 8 xx 5 xx 100 = 4 kcal`