A closed system undergoes a cycle in which heat is added at a temperature of 750 K isothermally with an initial and final specific entropy values of 2.5 kJ/kg K and 6.0

kJ/kg K respectively. If the rest of the cycle consists of an adiabatic expansion down to

a temperature of 415 K, an isothermal heat rejection to the initial entropy value and

finally, an adiabatic compression to the initial temperature, find the net heat transferred

during the cycle.

(b) 4 kg of fluid at a pressure of 250 kPa is compressed from a volume of 3.6 m3

to 1.2 m3

within a cylinder and piston assembly. Calculate the work done on the fluid.​