Question

What is the thermal efficiency of an engine? Can it ever be 100 percent? Why or why not?

a) Thermal efficiency is the ratio of work done to the heat input. It can be 100%.

b) Thermal efficiency is the ratio of heat output to work done. It can be 100%.

c) Thermal efficiency is always less than 100% due to energy losses.

d) Thermal efficiency is always greater than 100% due to energy gains.

Answer 1

Thermal efficiency is the ratio of useful energy output to the energy input in a heat engine. It can never be 100 percent due to energy losses.

Step-by-step explanation:

Thermal efficiency is the ratio of useful energy output to the energy input in a heat engine. It is calculated by dividing the net work output by the heat transferred into the engine. The thermal efficiency of an engine can never be 100 percent because there are always energy losses in the form of waste heat. These losses occur due to factors such as friction, heat conduction, and incomplete combustion. Therefore, option c) is correct: thermal efficiency is always less than 100% due to energy losses.