Q. No.A refrigerator works between 4°C and 30°C. 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)23.65W
(2)236.5W
(3)2365W
(4)2.365W
(1)23.65W
Figure below shows two paths that may be taken by a gas to go from a state A to a state C. 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-
(a) 380 J
(b) 500 J
(c) 460 J
(d) 300 J
One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure.
The change in internal energy of the gas during the transition is
(1) 20 kJ
(2) -20 kJ
(3) 20 J
(4) -12 kJ
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. 31°C
2. 41°C
3. 11°C
4. 21°C
A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected by the gas during the cycle is
(a)2 pV (b)4 pV
(c) (d)pV
One mole of an ideal gas from an initial state A undergoes via two processes. It first undergoes isothermal expansion from volume V to 3V and then its volume is reduced from 3V to V at constant pressure. The correct P-V diagram representing the two processes is -
An ideal gas goes from state \(A\) to state \(B\) via three different processes, as indicated in the \(P\text-V\) diagram. If \(Q_1,Q_2,Q_3\) indicates the heat absorbed by the gas along the three processes and \(\Delta U_1, \Delta U_2, \Delta U_3\) indicates the change in internal energy along the three processes respectively, then:
| 1. | \({Q}_1>{Q}_2>{Q}_3 \) and \(\Delta {U}_1=\Delta {U}_2=\Delta {U}_3\) |
| 2. | \({Q}_3>{Q}_2>{Q}_1\) and \(\Delta {U}_1=\Delta {U}_2=\Delta {U}_3\) |
| 3. | \({Q}_1={Q}_2={Q}_3\) and \(\Delta {U}_1>\Delta {U}_2>\Delta {U}_3\) |
| 4. | \({Q}_3>{Q}_2>{Q}_1\) and \(\Delta {U}_1>\Delta {U}_2>\Delta {U}_3\) |
A mass of diatomic gas (=1.4) at a pressure of 2 atm is compressed adiabatically so that its temperature rise from to The pressure of the gas is final state is-
(1) 28 atm
(2) 68.7 atm
(3) 256 atm
(4) 8 atm
In thermodynamic processes, which of the following statements is not true?
| 1. | In an adiabatic process, the system is insulated from the surroundings. |
| 2. | In an isochoric process, the pressure remains constant. |
| 3. | In an isothermal process, the temperature remains constant. |
| 4. | In an adiabatic process, \(P V^\gamma\) = constant. |
If Q, E and W denote respectively the heat added, change in internal energy and the work done in a closed cyclic process, then
(1) W=0
(2) Q=W=0
(3) E=0
(4) Q=0
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