A sample of ideal gas (gamma = 1.4) is heated at constant pressure. If 100 J of heat is supplied to the gas the work done by the gas is

A sample of ideal gas (gamma = 1.4) is heated at constant pressure. If

1.	A sample of ideal gas (gamma = 1.4) is heated at constant pressure. If 100 J of heat is supplied to the gas the work done by the gas is
Answer» 28.57 J 56.54 J 38.92 J 65.38 J Solution :At constant pressure, `Delta Q = nC_(P) Delta T` and `Delta U = nC_(V) Delta T` From the FIRST law of THERMODYNAMICS, `Delta W = Delta Q - Delta U = n(C_(P) - C_(V)) Delta T` `:. (Delta W)/(Delta Q) = (n(C_(P) - C_(V))Delta T)/(nC_(P)Delta T) = 1 - (C_(V))/(C_(P)) = 1-(1)/(GAMMA)` `= 1-(1)/(1.4) = (0.4)/(1.4) = (4)/(14) = (2)/(7)` or `Delta W = (2)/(7) Delta Q = (2)/(7) xx 100 J = 28.57 J`