EASY

Earn 100

An ideal Carnot engine working with source temperature $T_{1}$ and sink temperature $T_{2}$ , has efficiency $η$ . Then the value of the ratio $\frac{T_{1}}{T_{2}}$ is

100% studentsanswered this correctly

Important Questions on Thermodynamics

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

A Carnot engine of efficiency

40 %,

takes heat from a source maintained at a temperature of

500 K

. It is desired to have an engine of efficiency

60 %

. Then, the source temperature for the same sink temperature must be

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

Helium gas goes through a cycle $A B C D A$ (consisting of two isochoric and two isobaric lines) as shown in figure. The efficiency of this cycle is approximately

Question Image

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

The efficiency of carnot engine is

η

when its hot and cold reservoirs are maintained at temperature

T_{1}

and

T_{2}

, respectively. To increase the efficiency to

1.5 η

, the increase in temperature

(Δ T)

of the hot reservoir by keeping the cold one constant at

T_{2}

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

A carnot engine working between

200 K

and

500 K

has a work output of

900 J

per cycle. The amount of heat energy supplied to the engine from the source in each cycle is

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

Three Carnot engines operate in series between a heat source at a temperature

T_{1}

and a heat sink at temperature

T_{4}

(see figure). There are two other reservoirs at temperature

T_{2}

and

T_{3},

as shown, with

T_{1} > T_{2} > T_{3} > T_{4} .

The three engines are equally efficient if:

Question Image

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

A Carnot engine takes

300

calories of heat from a source at

500 K

and rejects

150

calories of heat to the sink. The temperature of the sink is

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

Two carnot engines

A

and

B

are connected in series in such a way that the work outputs are equal when the temperatures of hot and cold reservoirs of

A

are

800 K

and

T

, and of engine

B

are

T

and

300 K

, respectively. Then the temperature

T

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

A Carnot engine whose low-temperature reservoir is at

350 K

has an efficiency of

50 %

. It is desired to increase this to

60 %

. If the temperature of the low-temperature reservoir remains constant, then the temperature of the high-temperature reservoir must be increased by how many degrees?

HARD

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

Two ideal Carnot engines operate in a cascade (all heat given up by one engine is used by the other engine to produce work) between temperatures,

T_{1}

and

T_{2}

. The temperature of the hot reservoir of the first engine is

T_{1}

and the temperature of the cold reservoir of the second engine is

T_{2}

T

is the temperature of the sink of the first engine which is also the source for the second engine. How is

T

related to

T_{1}

and

T_{2}

, if both the engines perform an equal amount of work?

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

The efficiency of a Carnot engine depends upon

HARD

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

An engine runs between a reservoir at temperature

200 K

and

a

hot body which is initially at temperature of

600 K .

If the hot body cools down to a temperature of

400 K

in the process, then the maximum amount of work that the engine can do (while working in a cycle) is (the heat capacity of the hot body is

1 J / K)

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

A Carnot engine has an efficiency of

\frac{1}{6} .

When the temperature of the sink is reduced by

62 ℃

, its efficiency is doubled. The temperatures of the source and the sink are, respectively,

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

For a Carnot engine which of the following is false?

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

The efficiency of Carnot engine is

0.6

. It rejects

20 J

of heat to sink. The work done by the engine is

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

A Carnot engine is operating between a hot body and cold body maintained at temperature $T_{1}$ and $T_{2}$ respectively. Consider the following three cases

Case I : The temperature of the hot body is changed to $T_{1} + Δ T$ and cold body is at $T_{2}$

Case II : The temperature of the hot body is at $T_{1}$ and cold body is changed to $T_{2} + Δ T$

Case III : The temperature of the hot body is

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

An ideal Carnot's engine works between

227 °

and

57 ° C

. Find the efficiency of the engine.

HARD

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

Two Carnot engines

A

and

B

operate in series such that engine A absorbs heat at

T_{1}

and rejects heat to a sink at temperature

T

. Engine

B

absorbs half of the heat rejected by Engine

A

and rejects heat to the sink at

T_{3}

. When workdone in both the cases is equal, to value of

T

is :

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

A reservoir is at

827 ° C

and Carnot's engine takes a thousand

kilo calorie

of heat from it and exhausts it to a sink at

27 ° C

. What is the amount of work and the efficiency of the engine?

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

A Carnot engine having an efficiency of

\frac{1}{10}

is being used as a refrigerator. If the work done on the refrigerator is

10 J,

the amount of heat absorbed from the reservoir at a lower temperature is

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Heat Engines and Refrigerators

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:

An ideal Carnot engine working with source temperature T1 and sink temperature T2, has efficiency η. Then the value of the ratio T1T2 is

Important Questions on Thermodynamics

Learn and Prepare for any exam you want !

An ideal Carnot engine working with source temperature $T_{1}$ and sink temperature $T_{2}$ , has efficiency $η$ . Then the value of the ratio $\frac{T_{1}}{T_{2}}$ is