Question

A gasoline engine receives 200 J of energy from combustion and loses 150 J as heat to the exhaust. What is its efficiency?


75%

25%

33%

125%

Answer 1

Efficiency = \(\sf 1-\huge \frac{Q_2}{Q_1}\)

Answer 2

\(\sf Q_2\)= Heat lost and \(\sf Q_1\) = Input heat

Answer 3

When calculating the efficiency in %, multiply the result with 100

Answer 4

75%?

Answer 5

How?

Answer 6

150/200 = .75 x 100 = 75

Answer 7

\(\color{blue}{\text{Originally Posted by}}\) @Abhisar
Efficiency = \(\sf \huge 1-\frac{Q_2}{Q_1}\)
\(\color{blue}{\text{End of Quote}}\)

Answer 8

Isn't that still 75?

Answer 9

oops!
Sorry..correction..

Answer 10

\(\sf \frac{200-150}{200}\times 100 =?\)

Answer 11

Not getting it yet?

Answer 12

25?

Answer 13

Yes, that's \(\huge \checkmark\)

Answer 14

Thanks!

Answer 15

Welcome :)