1.

A petrol engine consumes 20 kg of petrol per hour. The calorific value of the fuel is1 xx 10^(7) cal/kg. The power of the engine is 84 kilowatt. Calculate the efficiency of the engine.

Answer»

`36 %`
`46 %`
`28 %`
`58 %`

Solution :Petrol consumed by the engine,
`m_(f) = 20/(60 xx 60) kg//s`
Heat released DUE to the combustion of fuel,
`Q = m_(f) xx ` calorific value of the fuel ` = 20/(60 xx 60) xx 1 xx 10^(7)`
` = 10^(6)/18 " cal/s" = 10^(6)/18 xx 4.2 " joule /s " = 700/3 ` kW
Power produced by the engine , `W = 84 kW`
` :. ` EFFECIENCY of the engine
` = W/Q xx 100 = 84/(700//3) xx 100 = 36% `


Discussion

No Comment Found

Related InterviewSolutions