Question

500g of water at temperature of 15°C is placed in a freezer. The freezer has a power rating of 100W and is 80% efficient.

1- Calculate the energy required to convert the water into ice at a temperature of -20°C.

2- How much energy is removed every second from the air in the freezer?

3- How long will it take the water to reach a temperature of -20°C?

4- Explain the process that cools the air in the freezer.

5- The freezer causes the room temperature to rise. Explain why.

Specific heat capacity of ice =2100J kg^-1K^-1; Specific heat capacity of water

=4180J kg^-1K^-1; Specific latent heat of fusion of water = 3.3x10⁵Jkg^-1

Answer 1