Thermodynamics (Physics) · Question 55

An electric heater supplies heat to a system at a rate of 100 W. If the system performs work at a rate of 75 J/s, then the rate at which internal energy increases will be :

1. 75 W
2. 25 W
3. 100 W
4. 125 W

In an adiabatic expansion, the temperature of one mole of an ideal monatomic gas ( = 5/3) decreases from 60 K to 50 K. The work done by the gas in the process is: (Take the universal gas constant as R = 8.3 J mol-1 K-1)

1. 166 J
2. 41.5 J
3. 83 J
4. 124.5 J

One mole of an ideal monatomic gas undergoes a cyclic process as shown in the figure. The total heat supplied to the gas is: [figure]

1. 800 J
2. 400 J
3. 500 J
4. 600 J

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