Question

There is a refrigerator running in a room, the heat flowing into the refrigerator from the outside is 40 J/s, and the refrigerator must consume 100 W to maintain the low temperature set in it. (1) What is the heat discharged from the refrigerator at this time?
(2) If the doors and windows of the room are closed, the temperature of the room rises by a few degrees per hour? Assume that the air heat capacity of the entire room is 400 kJ/K.

Answer 1

Answer:

(A) 140 j/sec (b) 1.26 K

Explanation:

We have given the heat heat flowing into the refrigerator = 40 J/sec

Work done = 40 W

(a) So the heat discharged from the refrigerator $=heat\ flowing\ in\ refrigerator+work\ done=40+100=140j/sec$

(b) Total heat absorbed =140 j/sec $=140\times 3600=504000j/hour$

Let the temperature be $\Delta T$

Heat absorbed per hour =504000 $[tex]=400\times 10^3\times \Delta T$

So  $\Delta T=\frac{504000}{400000}=1.26K$