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

MEDIUM

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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).

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Important Questions on Thermodynamics

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

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}

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

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

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

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

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

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

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

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

Which of the following statements is true? The entropy of the universe

MEDIUM

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

The change in entropy when a $30 g$ ice cube at $- 12 ° C$ is transformed into water at $100 ° C$ $($ in $J / K)$ is

$($ Take $ℓ n (\frac{273}{261}) = 0.04; ℓ n (\frac{373}{273}) = 0.312$ , $S_{ice} = 2100 J / kg - {}^{\circ}C,$ $S_{water} = 4200 J / kg - {}^{\circ}C, L_{f} = 3.33 \times 10^{5} J / kg)$

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:

MEDIUM

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

The second law of thermodynamics implies that :

HARD

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

Consider a cycle followed by an engine.
$1$ to $2$ is isothermal
$2$ to $3$ is adiabatic
$3$ to $1$ is adiabatic

Question Image
Such a process does not exist because

EASY

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

The law of thermodynamics which leads to the conclusion that it is impossible to convert 'all' the heat extracted from a hot source into work is :

HARD

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

The wavelength associated with the electron will be

EASY

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

Give the alternative statement of second law of thermodynamics?

EASY

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

Second law of thermodynamics is equivalent to which of the following statements?

Two solid blocks at temperatures T1 and T2T1<T2 are put in thermal contact for a long time inside an insulated container. Choose the correct statement(s).

Important Questions on Thermodynamics

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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).