Thermodynamics (Physics) · Question 3

Two gases A and B are filled at the same pressure in separate cylinders with movable pistons of radius rA and rB, respectively. On supplying an equal amount of heat to both the systems reversibly under constant pressure, the pistons of gas A and B are displaced by 16 cm and 9 cm, respectively. If the change in their internal energy is the same, then the ratio rArB is equal to

1. 2 3
2. 32
3. 43
4. 34

A thermodynamic system is taken through the cycle abcda. The work done by the gas along the path bc is: [figure]

1. Zero
2. 30 J
3. -90 J
4. -60 J

The equilibrium state of a thermodynamic system is described by Choose the most appropriate answer from the options given below.

1. A, B and E only
2. B, C and D only
3. A, B and C only
4. A, C and D only

A Carnot engine has an efficiency of 50\% when its source is at a temperature 327 . The temperature of the sink is :-

1. 15
2. 100
3. 200
4. 27

An ideal gas undergoes four different processes from the same initial state as shown in the figure below. Those processes are adiabatic, isothermal, isobaric and isochoric. The curve which represents the adiabatic process among 1, 2, 3 and 4 is [figure]

1. 1
2. 2
3. 3
4. 4

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