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

MEDIUM

JEE Main

IMPORTANT

Earn 100

An ideal gas goes through a reversible cycle $a \to b \to c \to d$ has the V - T diagram shown below. Process $d \to a a n d b \to c$ are adiabatic.

The corresponding P - V diagram for the process is (all figures are schematic and not drawn to scale) :

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Important Questions on Thermodynamics

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 4th April 2015>Q 87

Consider a spherical shell of radius R at temperature T. The black body radiation inside it can be considered as an ideal gas of photons with internal energy per unit volume

u = \frac{U}{V} \propto T^{4}

and pressure

p = \frac{1}{3} (\frac{U}{V})

. If the shell now undergoes an adiabatic expansion the relation between T and R is:

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 4th April 2015>Q 88

A solid body of constant heat capacity

1 J {(℃)}^{- 1}

is being heated by keeping it in contact with reservoirs in two ways: (i) Sequentially keeping in contact with 2 reservoirs such that each reservoir supplies the same amount of heat. (ii) Sequentially keeping in contact with

8

reservoirs such that each reservoir supplies the same amount of heat. In both, cases the body is brought from initial temperature

100 K

to final temperature

200 K

. Entropy change of the body in the two cases respectively is: Note: This question was awarded as a bonus since temperatures were given in centigrade instead of in Kelvin. Proper corrections are made in the question to avoid it.

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JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 19th April 2014>Q 89

A monoatomic gas is compressed from a volume of

2 m^{3}

to a volume of

1 m^{3}

at a constant pressure of

100 N m^{2}

. Then it is heated at constant volume by supplying

150 J

of energy. As a result, the internal energy of the gas

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JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 9th April 2014>Q 90

The equation of state for a gas is given by

PV = nRT + α V

, where n is the number of moles and

α

is a positive constant. The initial temperature and pressure of one mole of the gas contained in a cylinder are T₀ and P₀ respectively. The work done by the gas when its temperature doubles isobarically will be :

MEDIUM

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 6th April 2014>Q 91

One mole of diatomic ideal gas undergoes a cyclic process ABC as shown in figure. The process BC is adiabatic. The temperatures at A, B and C are 400 K, 800 K and 600 K respectively. Choose the correct statement :

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 - 7th April 2013>Q 92

The above

P - V

diagram represents the thermodynamic cycle of an engine, operating with an ideal mono-atomic gas. The amount of heat, extracted from the source in a single cycle, is:

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JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 24 June 2022 Shift 1>Q 93

A Carnot engine whose heat sinks is at

27 ° C

, has an efficiency of

25 %

. By how many degrees should the temperature of the source be changed to increase the efficiency by

100 %

of the original efficiency ?

MEDIUM

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 10 - Thermodynamics>JEE Main - 24 June 2022 Shift 2>Q 94

A Carnot engine takes

5000 kcal

of heat from a reservoir at

727 ° C

and gives heat to a sink at

127 ° C

. The work done by the engine is

An ideal gas goes through a reversible cycle a→b→c→d has the V - T diagram shown below. Process d→a and b→c are adiabatic. The corresponding P - V diagram for the process is (all figures are schematic and not drawn to scale) :

Important Questions on Thermodynamics

Learn and Prepare for any exam you want !

An ideal gas goes through a reversible cycle $a \to b \to c \to d$ has the V - T diagram shown below. Process $d \to a a n d b \to c$ are adiabatic.

The corresponding P - V diagram for the process is (all figures are schematic and not drawn to scale) :