Question

Explain the energy flow in a heat engine with a neat labelled
diagram and define the thermal efficiency of a heat engine.​

Answer 1

HEAT ENGINE :

• It is a thermodynamics machine which converts heat to work.

• The engine takes up heat from the source (at T1) and does certain magnitude of work. The rest heat is released to the sink (T2).

• T1 > T2

In the diagram you can see that , Q1 is being taken by engine to do W work and then Q2 is being delivered to the sink.

$\boxed{ \bf Q1 = W + Q2}$

Efficiency of engine :

• It is defined as the ratio of work done to heat taken in by the engine.

$\boxed{ \bf \therefore \: \eta = \dfrac{W}{Q1}}$

$\bf \implies \: \eta = \dfrac{Q1 - Q2}{Q1}$

$\boxed{ \bf \implies \: \eta = 1 - \dfrac{ Q2}{Q1}}$

Hope It Helps.