If the door of a refrigerator is kept open in a dosed room then room :

Options

A. falls
B. rises
C. remains same
D. depends on area of the room

Answer

B

Explanation

`AB` is isothermal change,
`therefore P_(1)V_(1)=P_(2)V_(2)` or `P_(2)=(P_(1)V_(1))/(V_(2))`
BC is adiabatic change `P_(2)P_(2)^(gamma)=P_(3)V_(1)^(gamma)`
`P_(1)V_(2)^(gamma-1)=P_(3)V_(1)^(gamma-1)`
as `V_(2) gt V_(1)` then `P_(3) gt P_(1)`
Area under the adiabatic curve is more than that under isothermal curve. during adiabatic curve gas is compressed by doing work on it. so its is negative and during isothermal curve gas undergoes expansion. ga does work. so it is positive. as negative work is more than positive work, the net work `W lt O`