An engine operates between a hot reservoir at and a cold reservoir at
PHYSICS · Single correct · A Level · Physics · Engineering physics · Engineering physics
Problem
An engine operates between a hot reservoir at 600K and a cold reservoir at 300K. An inventor claims it delivers an efficiency of 70%. Which statement is correct regarding this claim?
(a) The claim is possible because 70% is less than the theoretical efficiency TcTh−Tc for these temperatures.
(b) The claim is impossible because 70% exceeds the maximum Carnot efficiency for these temperatures.
(c) The claim is possible because efficiency depends only on the temperature difference, and ΔT=300K is large enough to allow 70%.
(d) The claim is impossible because efficiency cannot exceed 50% for any heat engine regardless of temperatures.