Question

What is the efficiency of an engine that does 576 J of work and exhausts 144 J of heat while taking in 720 J of heat?

A. 80%
B. 10%
C. 25%
D. 20%

Answer 1

the answe would be 80%

Answer 2

The efficiency of an engine is 80%.

(A) is correct option.

Step-by-step explanation:

Given that,

Work done = 576 J

Supplied heat = 720 J

Exhausts of heat = 144 J

We need to calculate the efficiency

Using formula of efficiency

`\eta=1-(Q_(2))/(Q_(1))`

Where, Q₁ = Supplied heat

Q₂ = Exhausts of heat

Put the value into the formula

`\eta=1-(144)/(720)`

`\eta=0.8*100`

`\eta=80\%`

Hence, The efficiency of an engine is 80%.