Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : Efficiency of a reversible heat engine will be highest at – 273 ° C temperature of cold reservoir. Reason R : The efficiency of Carnot’s engine depends not only on temperature of cold reservoir but it depends on the temperature of hot reservoir too and is given as η = 1 - T 2 T 1 In the light of the above statements, choose the correct answer from the options given below :

Both A and R are true and R is the correct explanation of A

Both A and R are true but R is NOT the correct explanation of A

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IMPORTANT

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Which of the following is an equivalent cyclic process corresponding to the thermodynamic cyclic given in the figure? Where, $1 \to 2$ is adiabatic. (Graphs are schematic and are not to scale)

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Important Questions on Thermodynamics

MEDIUM

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 9th January 2020 Shift 2>Q 56

Starting at temperature

300 K,

one mole of an ideal diatomic gas

(γ = 1.4)

is first compressed adiabatically from volume

V_{1}

V_{2} = \frac{V_{1}}{16} .

It is then allowed to expand isobarically to volume

2 V_{2}

. If all the processes are the quasi-static then the final temperature of the gas (in

K

) is (to the nearest integer) ___________.

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 9th April 2019 Shift 1>Q 57

Following figure shows two processes

A

and

B

for a gas. If

∆ Q_{A}

and

∆ Q_{B}

are the amount of heat absorbed by the system in two cases, and

∆ U_{A}

and

∆ U_{B}

are changes in internal energies, respectively, then:
Question Image

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JEE Main

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 9th April 2019 Shift 2>Q 58

The specific heats,

C_{p}

and

C_{v}

of a gas of diatomic molecules,

A,

are given (in units of

J m o l^{- 1} K^{- 1}

) by

29

and

22,

respectively. Another gas of diatomic molecules,

B,

has the corresponding values

30

and

21 .

If they are treated as ideal gases, then:

EASY

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IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 9th January 2019 Shift 1>Q 59

A gas can be taken from

A

B

via two different processes

ACB

and

ADB

When path

ACB

is used

60 J

of heat flows into the system and

30 J

of work is done by the system. If the path

ADB

is used then work done by the system is

10 J

, the heat flows into the system in the path

ADB

is:

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 9th January 2019 Shift 2>Q 60

Two carnot engines

A

and

B

are operated in series. The first one,

A,

receives heat at

T_{1} (= 600 K)

and rejects to a reservoir at temperature

T_{2} .

The second engine

B

receives heat rejected by the first engine and, in turn, rejects to a heat reservoir at

T_{3} (= 400 K) .

Calculate the temperature

T_{2}

if the work outputs of the two engines are equal:

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 8th April 2019 Shift 2>Q 61

The given diagram shows four processes i.e., isochoric, isobaric, isothermal and adiabatic. The correct assignment of the processes, in the same order is given by:
Question Image

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 10th April 2019 Shift 1>Q 62

n

moles of an ideal gas with constant volume heat capacity

C_{v}

undergo an isobaric expansion by certain volume. The ratio of the work done in the process, to the heat supplied is:

MEDIUM

JEE Main

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 10th April 2019 Shift 1>Q 63

A cylinder with fixed capacity of

67.2

litre contains helium gas at STP. The amount of heat needed to raise the temperature of the gas by

20 ° C

is:
[Given that

R = 8.31 J m o l^{- 1} K^{- 1}]

Which of the following is an equivalent cyclic process corresponding to the thermodynamic cyclic given in the figure? Where, 1→2 is adiabatic. (Graphs are schematic and are not to scale)

Important Questions on Thermodynamics

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Which of the following is an equivalent cyclic process corresponding to the thermodynamic cyclic given in the figure? Where, $1 \to 2$ is adiabatic. (Graphs are schematic and are not to scale)