A stream engine delivers `5.4xx10^(8)J` of work per minute and absorbs `3.6xx10^(9)J` of heat per minute from its boiler. What is the efficiency of the engine? How much heat is wasted per minute?

Options

A. `3.1xx10^(9)"min"^(-1)`
B. `2xx10^(9)"min"^(-1)`
C. `4xx10^(9)"min"^(-1)`
D. `6xx10^(9)"min"^(-1)`

Answer

B

Explanation

Here , `Q_(1)` = Heat absorbed per minute
`Q_(2)` = Heat rejected per minute
We know that `eta=(W)/(Q_(1))XX100`
`therefore" " eta=(5.4xx10^(8)J)/(3.6xx10^(9)J)xx100=(3)/(10)xx100=15%`
Also using the relation , `Q_(1)=W+Q_(2)` , we get
`Q_(2)=Q_(1)-W`
`=30xx10^(8)-5.4xx10^(8)-5.4xx10^(8)`
= `30.6xx10^(8)J//"min"`
= `3.06xx10^(9)J//"min"`
`=3.1xx10^(9)J//"min"`