Question
A refrigerator works between 4o C and 30o C. It is required to remove 600 calories of heat every second in order to keep the temperature of the refrigerated space constant. The power required is (Take 1 cal = 4.2 Joules)
-
23.65 W
-
236.5 W
-
2365 W
-
2.365 W
Solution
B.
236.5 W
Given,
Temperature of the source, T = 30o C = 30 + 273 = 303 K
Temperature of sink, T2 = 4o C = 4 + 273 = 277 K
We know,
where, Q2 is the amount of heat drawn from the sink at T2,
W is the work done on the working substance,
Q1 is the amount of heat rejected to source at room temperature T1.
That is,
