A real (non-Carnot) heat engine, operating between heat reservoirs at temperatures of and performs 4.3 kJ of net work and rejects of heat in a single cycle. The thermal efficiency of this heat engine is closest to

Complete Question

A real (non-Carnot) heat engine, operating between heat reservoirs at temperatures of 650 K and 270 K and performs 4.3 kJ of net work and rejects 8.00 kJ of heat in a single cycle. The thermal efficiency of this heat engine is closest to A) 0.35 B) 0.31. C) 0.28. D) 0.38. E) 0.42.

The correct option is A

Explanation:

From the question we are told that

     The first operating temperature is  

     The second operating temperature is  

     The net workdone is  ( output of the engine )

     The amount of heat energy rejected is  

Generally a heat engine convert heat from a high temperature  to mechanical energy and then reject the remaining heat so the absorbed by the engine  is  

Generally the thermal  efficiency is mathematically represented as

Here out is the output of the engine

and  in is the input of the engine

=>  

=>