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The sprinkling of water reduces the temperature of a closed room slightly because,

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Important Questions on Thermal Properties of Matter

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Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

Steam at

100^{o} C

is passed into

20 g

of water at

10^{o} C .

When water acquires a temperature of

80^{o} C,

the mass of water present will be:
[Take specific heat of water

= 1 c a l g^{- 1 o} C^{- 1}

and latent heat of steam

= 540 c a l g^{- 1}]

EASY

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

Heat required to melt $1 g$ of ice is $80 cal$ . A man melts $60 g$ of ice by chewing in one minute. His power is______

EASY

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

In an experiment, a sphere of aluminium of mass

0.20 kg

is heated up to

150 ° C

. Immediately, it is put into water of volume

150 cc

27^{o} C

kept in a calorimeter of water equivalent to

0.025 kg

. The final temperature of the system is

40^{o} C

. The specific heat of the aluminium is(take

4.2 Joule = 1 calorie

)

EASY

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

A closed bottle containing water at

30^{o} C

is open on the surface of the moon. Then-

EASY

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

The quantities of heat required to raise the temperature of two solid copper spheres of radii

r_{1}

and

r_{2} (r_{1} = 1.5 r_{2})

through

1 K

are in the ratio:

EASY

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

Two systems are in thermal equilibrium. The quantity which is common for them is

EASY

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

A steam engine intakes $50 g$ of steam at $100 ° C$ per minute and cools it down to $20 ° C$ . If latent heat of vaporization of steam is $540 cal g^{- 1}$ , then the heat rejected by the steam engine per minute is _____ $\times 10^{3} cal$

(Given : specific heat capacity of water : $1 cal g^{- 1} {{}^{\circ}C}^{- 1}$ )

HARD

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

A graph of vapour pressure and temperature for three different liquids

X, Y

and

Z

is shown below:
Question Image

The following inferences are made:

(A) X

has higher intermolecular interactions compared to

Y .

(B) X

has lower intermolecular interactions compared to

Y .

(C) Z

has lower intermolecular interactions compared to

Y .

The correct inferences is/are:

EASY

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

Latent heat of vaporisation of water is

22.6 \times 10^{5} J {kg}^{- 1}

. The amount of heat needed to convert

100 kg

of water into vapour at

100 ° C

HARD

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

A thermally insulated cubical box of side length $20 cm$ and wall thickness $2 cm$ containing $2 kg$ of ice is closed on all sides. The mass of ice melted in $10$ hours is (Thermal conductivity of the material of the box $= 0.01 {Wm}^{- 1} K^{- 1},$ latent heat of ice $= 360 \times 10^{3} J {kg}^{- 1}$ and ambient temperature $= 40 ° C$ )

EASY

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

If pressure increased on a piece of wax, the melting point of wax

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Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

A thermally insulated vessel contains

150 g

of water at

0 ° C

. Then the air from the vessel is pumped out adiabatically. A fraction of water turns into ice and the rest evaporates at

0 ° C

itself. The mass of evaporated water will be closest to: (Latent heat of vaporization of water

= 2.10 \times 10^{6} J k g^{- 1}

and Latent heat of Fusion of water

= 3.36 \times 10^{5} J k g^{- 1}

)

EASY

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

The physical quantity that determines whether or not a given system

A

is in thermal equilibrium with another system

B

is called

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Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

50 g

of ice at

0 ° C

is mixed with

50 g

of water at

80 ° C

. If the latent heat of ice is

80 cal g^{- 1}

and specific heat of water is

1 cal g^{- 1} ° C^{- 1}

, then the final temperature of mixture is

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Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

35^{o} C,

the vapour pressure of

C S_{2},

512 mmHg

and that of acetone is

144 m m H g .

A solution of

C S_{2}

in acetone has a total vapour pressure of

600 m m H g

. The false statement amongst the following is:

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Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

A solid metal weighing

150 g

melts at its melting point of

800 ° C

by providing heat at the rate of

100 W

. The time taken for it to completely melt at the same temperature is

4 \min

. What is the specific latent heat of fusion of the metal?

HARD

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

Explain the following temperature versus time graph:

Question Image

HARD

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

10 H

inductor carries a current of

20 A

. If the energy stored in this inductor melts ice at

0 ° C,

then the mass of the ice melted is

[

Latent heat of ice

= 2.26 \times 10^{3} J {kg}^{- 1}]

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Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

1 kg

of water, at

20 ° C

is heated in an electric kettle whose heating element has a mean (temperature averaged) resistance of

20 Ω .

The rms voltage in the mains is

200 V

. Ignoring heat loss from the kettle, time taken for water to evaporate fully is close to
[ Specific heat of water

= 4200 J {kg}^{- 1} ° C^{- 1}

Latent heat of water

= 2260 k J k g^{- 1}

]

EASY

Physics>Heat and Thermodynamics>Thermal Properties of Matter>Change of State

A piece of ice falls from a height

h

so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of

h

is:
(Latent heat of ice is

3.4 \times 10^{5} {J kg}^{- 1}

and

g = 10 {N kg}^{- 1}

)

The sprinkling of water reduces the temperature of a closed room slightly because,

Important Questions on Thermal Properties of Matter

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