Refrigerator Or Heat Pump MCQ - Practice Questions with Answers

For a refrigerator which of the following statements is true 

1) A refrigerator is basically a heat engine running in the reverse direction 

2) Coefficient of performance  = Heat extracted / Work done 

3) The relation b/w coefficient of performance and efficiency of the refrigerator is 

The temperature inside a refrigerator is $t_2^{\circ} \mathrm{C}$ and the room temperature is $t_1^{\circ} \mathrm{C}$. The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be:

A Carnot engine, having the efficiency of a heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absorbed from the reservoir at a lower temperature is:

A refrigerator works between 4°C and 30°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)

The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is - 20°C, the temperature of the surroundings to which it rejects heat is:

A Carnot engine having an efficiency of $\frac{1}{10}$ as a heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absorbed from the reservoir at a lower temperature is:

A Carnot engine works as a refrigerator between 250 K and 300 K. It receives 500 cal heat from the reservoir at the lower temperature. The amount of work done (in J) in each cycle to operate the refrigerator is:

A refrigerator freezes 1 kg of water at $0^{\circ} \mathrm{C}$ in 3 minutes. The room temperature is $27^{\circ} \mathrm{C}$. The latent heat of fusion of ice is 80 cal/g then choose the incorrect statement

In a refrigerator, one removes heat from a lower temperature and deposits it to the surroundings at a higher temperature. In this process, mechanical work has to be done, which is provided by an electrical motor. If the motor is of 1 kW power and heat is transferred from $-3^{\circ} \mathrm{C}$ to $27^{\circ} \mathrm{C}$, find the heat taken out of the refrigerator per second assuming its efficiency is $50 \%$ of a perfect engine.

If the coefficient of performance of a refrigerator is 5 and 6 operates at the room temperature $\left(27^{\circ} \mathrm{C}\right)$, find the temperature inside the refrigerator.