In an ideal refrigerator, heat from inside at 280 K is transferred to a room at 300 K. What is the amount of heat (in joule) which will be transferred to the room for each joule of electrical energy consumed in the process ?

Options

A. 12 J
B. 13 J
C. 15 J
D. 18 J

Answer

C

Explanation

For a refrigerator, the coefficient of performance,
`beta=T_(2)/(T_(1)-T_(2))=280/(300-280)=280/20=14`
and `beta=Q_(2)/W" "thereforeQ_(2)=betaW=14xx1=14J`
where `Q_(2)` = Heat taken from the cold reservoir
and W = Work done on it
`Q_(1)` = Heat transferred to the room
By the law of conservation of energy,
`Q_(1)=Q_(2)+W=14+1=15J`