Question

a heat engine gives out 400J of heat energy as the useful work.calculate the energy given to it as input if its efficiency is 40%?​

Answer 1

Answer:

E(efficiency) = E(out) / E(in)

.4 = 400 J / E (in)

E (in) = 1000 J

Answer 2

Heat input : 1000J

What is efficiency of a heat engine ?

The efficiency of a heat engine  is defined as the ratio of work done by the heat engine absorbed per cycle.

Given : work output = 400 J

          Efficiency = 40 % = 0.4

          heat input = ?

Efficiency = work output / heat input

                0.4 = 400/heat input  

heat input : 1000J

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