Second Law Of Thermodynamics

An engine has an efficiency of $\frac{1}{6}$. When the temperature of the sink is reduced by ${62}^{0}C$, its efficiency is doubled. the temperature of the source is:

1. 124^oC

2. 37^oC

3. 62^oC

4. 99^oC

When kg of ice at C melts into the water at C, the resulting change in its entropy, taking the latent heat of ice to be cal/gm, is:
1. cal/K
2. cal/K
3. cal/K
4. cal/K

The coefficient of performance of a refrigerator is If the temperature inside the freezer is the temperature of the surroundings to which it rejects heat is:
1.
2.
3.
4.

The temperature inside a refrigerator (reversible process) is t₂^oC and the room temperature is t₁^oC. The amount of heat delivered to the room for each joule of electrical energy consumed, ideally, will be:

1. $\frac{t_1}{t_1-t_2}$

2. $\frac{t_1+273}{t_1-t_2}$

3. $\frac{t_2+273}{t_1+t_2}$

4. $\frac{t_1+t_2}{t_1+273}$

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

The efficiency of a Carnot engine depends upon:

1. the temperature of the sink only.

2. the temperatures of the source and the sink.

3. the volume of the cylinder of the engine.

4. the temperature of the source only.