A carnot engine having an efficiency of$\frac{1}{10}$th of 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 -

(a) 1 J

(b) 90 J

(c) 99 J

(d0 100 J

Concept Questions :-

Heat engine and refrigerator
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

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

(a)$\frac{{t}_{1}}{{t}_{1}-{t}_{2}}$      (b) $\frac{{t}_{1}+273}{{t}_{1}-{t}_{2}}$

(c) $\frac{{t}_{2}+273}{{t}_{1}-{t}_{2}}$    (d) $\frac{{t}_{1}+{t}_{2}}{{t}_{1}+273}$

Concept Questions :-

Heat engine and refrigerator
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A gas is compressed isothermally to half its initial volume. The same gas is compressed separately through an adiabatic process until its volume is again reduced to half .Then -

(a) compressing the gas through adiabatic process will require more work to be done
(b) compressing the gas isothermally or adiabatically will require the  same amount work
(c) which of the case (whether compression through isothermal or through adiabatic process) requires more work will depend upon the atomicity of the gas
(d) compressing the gas isothermally will require more work to be done

Concept Questions :-

Work done by gas
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

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)

(a)23.65W
(b)236.5W
(c)2365W
(d)2.365W

Concept Questions :-

Heat engine and refrigerator
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

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

Concept Questions :-

First law of thermodynamics
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

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

(a) 20 kJ

(b) -20 kJ

(c) 20 J

(d) -12 kJ

Concept Questions :-

Molar Specific heat
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Difficulty Level:

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

(b) Isobaric

(c) Isochoric

(d) Isothermal

Concept Questions :-

Work done by gas
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

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  -

(a)31°C

(b)41°C

(c)11°C

(d)21°C

Concept Questions :-

Heat engine and refrigerator
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

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

(a) ρoV

(b) 2ρoVo

(c) ρoVo/2

(d)zero

Concept Questions :-

Cyclic process
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Difficulty Level:

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

(a)2000J

(b)1000J

(c)Zero

(d)-2000J

Concept Questions :-

Work done by gas