EASY

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Which material has a high latent heat of fusion particular to its composition?

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Important Questions on Heat and Temperature

EASY

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical State

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

MEDIUM

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical 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

HARD

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical 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}]

EASY

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical State

The physical quantity that determines whether or not a given system

A

is in thermal equilibrium with another system

B

is called

EASY

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical 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}

)

EASY

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical 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______

HARD

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical 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

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical State

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

MEDIUM

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical 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}

]

MEDIUM

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical 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

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical 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

EASY

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical State

A closed bottle containing water at

30^{o} C

is open on the surface of the moon. Then-

MEDIUM

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical 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

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical 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

)

MEDIUM

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical State

An experiment takes

10 \min

to raise the temperature of water from

0 ° C

and

100 ° C

and another

55 \min

to convert it totally into steam by a stabilized heater. The latent heat of vaporization comes out to be,

MEDIUM

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical State

2 g of water condenses when passed through 40 g of water initially at 25

℃

. The condensation of steam raises the temperature of water to 54.3

℃

. What is the latent heat of steam?

MEDIUM

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical State

One

gram

of steam at

100 ° C

and equal mass of ice at

0 ° C

are mixed. The temperature of the mixture in steady state will be, (Latent heat of steam

= 540 c a l g^{- 1}

, latent heat of ice

= 80 c a l g^{- 1}

MEDIUM

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical State

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

MEDIUM

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical State

A cooking vessel on a slow burner contains 5 kg of water and an unknown mass of ice in equilibrium at 0^oC at time t = 0. The temperature of the mixture is measured at various times and the result is plotted as shown in diagram. During the first 50 min the mixture remains at 0^oC. From 50 min to 60 min, the temperature increases to 2^oC. Neglecting the heat capacity of the heat capacity of the vessel, the initial mass of the ice is
Question Image

HARD

Science>Physics>Heat and Temperature>Effects of Heat: Change in Physical State

Steam at

100 ° C

is passed into

1.1 kg

of water. It is contained in a calorimeter, which is equivalent to

0.02 kg

15 ° C

, till the temperature of the calorimeter and its contents rises to

80 ° C

. The mass of the steam condensed in

kg

Which material has a high latent heat of fusion particular to its composition?

Important Questions on Heat and Temperature

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