A technician claims to have built a prototype heat pump that transfers 5000J of heat from a cold reservoir at 275K to a hot reservoir at 315K while consuming only 300J of work per cycle.
(a) Calculate the change in entropy of (i) the cold reservoir, (ii) the hot reservoir, and (iii) the universe for one cycle of the claimed device.
(b) On the basis of your result in (i), comment on the possibility of the prototype operating as described.
(c) If the transfer of 5000J is carried out reversibly between the same two reservoirs, determine the minimum amount of work that would have to be supplied per cycle.