Question

During each cycle of operation a refrigerator absorbs 56 cal from the freezer compartment and expels 81 cal tothe room. If one cycle occurs every 10 s, how many minutes will it take to freeze 570 g of water, initially at 0°C?(Lv = 80 cal/g

Answer 1

138.18 minutes

Step-by-step explanation:

`L_v` = Latent heat of water at 0°C = 80 cal/g

m = Mass of water = 570 g

Heat removed for freezing

`Q=mL_v\\\Rightarrow Q=570* 80\\\Rightarrow Q=45600\ cal`

Let N be the number of cycles and each cycle removes 56 cal from the freezer.

So,

`55* N=45600\\\Rightarrow N=(45600)/(55)`

Each cycle takes 10 seconds so the total time would be

`(45600)/(55)* (10)/(60)=138.18\ minutes`

The total time taken to freeze 138.18 minutes