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

Subtopic:  Heat Engine & Refrigerator (OLD NCERT) |
 58%
From NCERT
NEET - 2015
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A thermodynamic system undergoes cyclic process ABCDA as shown in figure. The work done by the system in the cycle is



(1) ρoV

(2) 2ρoVo

(3) ρoVo/2

(4)zero

Subtopic:  Cyclic Process |
 74%
From NCERT
NEET - 2014
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A gas is taken through the cycle A→B→C→A, as shown. What is the net work done by the gas?

(1)2000J

(2)1000J

(3)Zero

(4)-2000J

Subtopic:  Work Done by a Gas |
 70%
From NCERT
NEET - 2013
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During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of CP/CV for the gas is equal to:

1. 4/3 2. 2
3. 5/3 4. 3/2
Subtopic:  Types of Processes | Molar Specific Heat |
 64%
From NCERT
NEET - 2013
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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)12pV                                    (d)pV

Subtopic:  First Law of Thermodynamics |
 76%
From NCERT
NEET - 2012
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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 -

Subtopic:  Types of Processes |
 75%
From NCERT
NEET - 2012
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An ideal gas goes from state A to state B via three different processes, as indicated in the P-V diagram. If Q1, Q2, Q3 indicates the heat absorbed by the gas along the three processes and U1, U2, U3 indicates the change in internal energy along the three processes respectively, then:

1. \(\mathrm{Q}_1>\mathrm{Q}_2>\mathrm{Q}_3 \) and \(\Delta \mathrm{U}_1=\Delta \mathrm{U}_2=\Delta \mathrm{U}_3\)
2. \(\mathrm{Q}_3>\mathrm{Q}_2>\mathrm{Q}_1\) and \(\Delta \mathrm{U}_1=\Delta \mathrm{U}_2=\Delta \mathrm{U}_3\)
3. \(\mathrm{Q}_1=\mathrm{Q}_2=\mathrm{Q}_3\) and \(\Delta \mathrm{U}_1>\Delta \mathrm{U}_2>\Delta \mathrm{U}_3\)
4. \(\mathrm{Q}_3>\mathrm{Q}_2>\mathrm{Q}_1\) and \(\Delta \mathrm{U}_1>\Delta \mathrm{U}_2>\Delta \mathrm{U}_3\)

Subtopic:  First Law of Thermodynamics |
 80%
From NCERT
NEET - 2012
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A mass of diatomic gas (γ=1.4) at a pressure of 2 atm is compressed adiabatically so that its temperature rise from 27°C to 927°C. The pressure of the gas is final state is-

(1) 28 atm                                           

(2) 68.7 atm

(3) 256 atm                                           

(4) 8 atm

Subtopic:  Types of Processes |
 66%
From NCERT
NEET - 2011
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If U and W represent the increase in internal energy and work done by the system respectively in a thermodynamical process,which of the following is true?

(1) U=-W, in a adiabatic process

(2) U=W, in a isothermal process

(3) U=W, in adiabatic process

(4) U=-W,in a isothermal process 

Subtopic:  Types of Processes |
 79%
From NCERT
NEET - 2010
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A monoatomic gas at pressure p1 and V1 is compressed adiabatically to 18th its original volume. What is the final pressure of the gas ?

(1) 64 p1                                   

(2) p1

(3) 16 p1                                   

(4) 32 p1

Subtopic:  Types of Processes |
 72%
From NCERT
NEET - 2010
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