Thermodynamics (Physics) · Question 8

An ideal gas follows a process described by the equation PV2 = C from the initial (P1, V1, T1) to final (P2, V2, T2) thermodynamic states, where C is a constant. Then

1. If P1 > P2 then V1 > V2
2. If P1 > P2 then T1 < T2
3. If V2 > V1 then T2 > T1
4. If V2 > V1 then T2 < T1

Two cylinders A and B of equal capacity are connected to each other via a stop cock. A contains an ideal gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stop cock is suddenly opened. The process is :

1. adiabatic
2. isochoric
3. isobaric
4. isothermal

In which of the following processes, heat is neither absorbed nor released by a system?

1. adiabatic
2. isobaric
3. isochoric
4. isothermal

A sample of 0.1 g of water at 100°C and normal pressure (1.013 105 N m-2) requires 54 cal of heat energy to convert to steam at 100°C. If the volume of the steam produced is 167.1 cc, the change in internal energy of the sample, is

1. 104.3 J
2. 208.7 J
3. 42.2 J
4. 84.5 J

The volume (V) of a monatomic gas varies with its temperature (T), as shown in the graph. The ratio of work done by the gas, to the heat absorbed by it, when it undergoes a change from state A to state B, is [figure]

1. 25
2. 23
3. 13
4. 27

The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is

1. 26.8%
2. 20%
3. 6.25%
4. 12.5%

Thermodynamic processes are indicated in the following diagram. [figure] Match the following

1. (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)
2. (a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)
3. (a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)
4. (a)-(i), (b)-(iii), (c)-(iv), (d)-(ii)

A Carnot engine having an efficiency of 110 as 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 lower temperature is

1. 90 J
2. 99 J
3. 100 J
4. 1 J

A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half. Then

1. Compressing the gas isothermally or adiabatically will require the same amount of work.
2. Which of the case (whether compression through isothermal or through adiabatic process) requires more work will depend upon the atomicity of the gas.
3. Compressing the gas isothermally will require more work to be done.
4. Compressing the gas through adiabatic process will require more work to be done.

A refrigerator works between 4 and 30 . 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)

1. 236.5 W
2. 2365 W
3. 2.365 W
4. 23.65 W