An ice cube of mass 30 g at 0 0 C is left sitting on the kitchen table where it gradually melts and reaches the kitchen temperature of 25 0 C . The latent heat of fusion for ice is 333 J · g - 1 and the specific heat of water is 4 . 2 J · g - 1 · K - 1 . Select the correct statement(s) about this process. (All numerical values in the answers are rounded to the closest integer.)

The entropy of the kitchen does not change

The entropy change of the kitchen is - 48 J · K - 1

EASY

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Which of the following statements is correct for any thermodynamics system?

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Important Questions on Thermodynamics

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

An ideal gas is expanded from

(p_{1}, V_{1}, T_{1}) to (p_{2}, V_{2}, T_{2})

under different conditions. The correct statement(s) among the following is(are)

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

One mole of an ideal monatomic gas undergoes the following four reversible processes:
Step

1 :

It is first compressed adiabatically from volume

V_{1}

1 m^{2} .

Step

2 :

then expanded isothermally to volume

10 m^{3}

Step

3 :

then expanded adiabatically to volume

V_{3}

Step

4 :

then compressed isothermally to volume

V_{1} .

If the efficiency of the above cycle is

\frac{3}{4}

then

V_{1}

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

An ice cube of mass

30 g

0^{0} C

is left sitting on the kitchen table where it gradually melts and reaches the kitchen temperature of

25^{0} C

. The latent heat of fusion for ice is

333 J \cdot g^{- 1}

and the specific heat of water is

4.2 J \cdot g^{- 1} \cdot K^{- 1}

. Select the correct statement(s) about this process. (All numerical values in the answers are rounded to the closest integer.)

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

"Heat cannot be itself flow from a body at lower temperature to a body at higher temperature". This statement corresponds to

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

Consider a two stage Carnot engine. In the first stage heat

Q_{1}

is absorbed at temperature

T

and heat

Q_{2}

is expelled at temperature

α T

(where

α < 1

). In the second stage heat

Q_{2}

is absorbed at temperature

α T

and heat

Q_{3}

is expelled at temperature

β T (β < α) .

The efficiency of the Carnot engine will be

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

What will be the efficiency of a Carnot engine if it takes heat from reservoir, at

100 ° C

and rejects heat to a sink at,

50 ° C

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

Two solid blocks at temperatures

T_{1}

and

T_{2} (T_{1} < T_{2})

are put in thermal contact for a long time inside an insulated container. Choose the correct statement(s).

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

A number of carnot engines are operated at identical cold reservoir temperatures $(T_{L})$ . However, their hot reservoir temperatures are kept different. A graph of the efficiency of the engines versus hot reservoir temperature $(T_{H})$ is plotted. The correct graphical representation is

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

The carnot heat engine have an efficiency of

50 % .

The temperature of sink is maintained at

500 K .

To increase the efficiency upto

80 %,

the increment in the source temperature is

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

By leaving the door of a small standard domestic refrigerator open, it is not possible to cool a room, because it violates the ______

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

An engine operating between the boiling and freezing points of water will have

A. Efficiency more than $27 %$ .

B. Efficiency less than the efficiency of a Carnot engine operating between the same two temperatures.

C. Efficiency equal to $27 %$ .

D. Efficiency less than $27 %$ .

Choose the correct answer from the options given below

HARD

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

Graphs below show the entropy versus energy $U$ of two systems $1$ and $2$ at constant volume. The initial energies of the systems are indicated by $U_{1, i}$ and $U_{2, i},$ respectively. Graphs are drawn to the same scale. The systems are then brought into thermal contact with each other. Assume that, at all times the combined energy of the two systems remains constant. Choose the most appropriate option indicating the energies of the two systems and the total entropy after they achieve the equilibrium.

Question Image

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

For which of the following processes, entropy change is zero?

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

Entropy of the universe tends to be

HARD

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

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.

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

According to the third law of thermodynamics which one of the following quantities for a perfectly crystalline solid is zero at absolute zero?

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

When you make ice cubes, the entropy of water

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

Given the following entropy values $(i n J K^{- 1} m o l^{- 1})$ at 298 K and 1 atm : $H_{2} (g) : 130.6, C l_{2} (g) : 223.0, H C l (g) : 186.7.$ The entropy change $(i n J K^{- 1} m o l^{- 1})$ for the reaction

$H_{2} (g) + C l_{2} (g) \overset{}{\to} 2 H C l (g) i s$

HARD

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

Give at least two statements of the second law of thermodynamics.

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Second Law of Thermodynamics

Work done by an engine is $(Q_{1} + Q_{2}) J$ when a heat engine absorbs $Q_{1}$ heat at $T_{1}$ temperature and $Q_{2}$ heat at $T_{2}$ temperature. This data:

Which of the following statements is correct for any thermodynamics system?

Important Questions on Thermodynamics

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