The internal energy of an ideal gas increases in:
1. Adiabatic expansion
2. Adiabatic compression
3. Isothermal expansion
4. Isothermal compression
A refrigerator whose coefficient of performance is 5 extracts heat from the cooling chamber at a rate of 250 J per cycle. For refrigeration, the work done per cycle is:
1. 150 J
2. 200 J
3. 100 J
4. 50 J
\(0.04\) mole of an ideal monatomic gas is allowed to expand adiabatically so that its temperature changes from \(800~\text{K}\) to \(500~\text{K}\). The work done during expansion is nearly equal to:
1. | \(129.6\) J | 2. | \(-129.6\) J |
3. | \(149.6\) J | 4. | \(-149.6\) J |
Which of the following is true for the molar heat capacity of an ideal gas?
1. | It cannot be negative. |
2. | It has only two values \(\left(C_P \text { and } C_V\right)\). |
3. | It can have any value. |
4. | It cannot be zero. |
1. \(V_1= V_2\)
2. \(V_1> V_2\)
3. \(V_1< V_2\)
4. \(V_1\ge V_2\)
A heat engine is working between 200 K and 400 K. The efficiency of the heat engine may be:
1. 20%
2. 40%
3. 50%
4. All of these
In the cyclic process shown in the pressure-volume \((P-V)\) diagram, the change in internal energy is equal to:
1.
2.
3.
4. zero
If a refrigerator extracts heat 'a' from the cold reservoir and 'b' is the heat released from the hot reservoir, then the work done on the refrigerant (system) is:
1. a + b
2.
3. a
4.