Question

In an isothermal reversible compression of an ideal gas the sign of q, AS and w are respectively 

(a) +, -, – 

(b) -, +, – 

(c) +, -, +

(d) -, -, +

Answer 1

(d) -, -, +

During compression, energy of the system increases, in isothermal condition, to maintain temperature constant, heat is liberated from the system. Hence q is negative. During compression entropy decreases. During compression work is done on the system, hence w is positive.