Thermodynamics (Physics) · Question 19

The temperature inside a refrigerator is t2 C and the room temperature is t1 C. The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be

1. t1t1 - t2
2. t1 + 273t1 - t2
3. t2 + 273t1 - t2
4. t1 + t2t1 + 273

An ideal gas is compressed to half its initial volume by means of several processes. Which of the process results in the maximum work done on the gas ?

1. Isochoric
2. Isothermal
3. Adiabatic
4. Isobaric

The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is -20 C, the temperature of the surroundings to which it rejects heat is

1. 11 C
2. 21 C
3. 31 C
4. 41 C

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. 1 J
3. 100 J
4. 99 J

One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure. [figure] The change in internal energy of the gas during the transition is

1. 20 J
2. -12 kJ
3. 20 kJ
4. -20 kJ

Figure below shows two paths that may be taken by a gas to go from a state A to a state C. [figure] In process AB, 400 J of heat is added to the system and in process BC, 100 J of heat is added to the system. The heat absorbed by the system in the process AC will be

1. 460 J
2. 300 J
3. 380 J
4. 500 J

A monatomic gas at a pressure P, having a volume V expands isothermally to a volume 2V and then adiabatically to a volume 16V. The final pressure of the gas is (Take = 5/3)

1. 64P
2. 32P
3. P/64
4. 16P

A thermodynamic system undergoes cyclic process ABCDA as shown in figure. The work done by the system in the cycle is [figure]

1. P0V0
2. 2P0V0
3. P0V02
4. zero

The molar specific heats of an ideal gas at constant pressure and volume are denoted by Cp and Cv, respectively. If = CpCv and R is the universal gas constant, then Cv is equal to

1. ( - 1)R
2. R
3. 1 + 1 -
4. R( - 1)

A gas is taken through the cycle A B C A, as shown. What is the net work done by the gas? [figure]

1. Zero
2. - 2000 J
3. 2000 J
4. 1000 J