The specific heat capacity of a substance A is 3 , 800 J kg - 1 K - 1 and that of a substance B is 400 J kg - 1 K - 1 . Which of the two substances is a good conductor of heat? Give a reason for your answer.

The specific heat capacity of a body is the amount of heat required to increase the temperature of a unit mass of that body through 1 ° C or 1 K . So substance B is a good conductor of heat because its specific heat capacity is low, due to this it takes less heat to raise its temperature and transfer more amount of heat through it compared to substance A . All the conductors will have less specific heat capacity.

EASY

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When a substance melts, the required energy is called a specific latent heat of vaporisation.

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Important Questions on Thermal Physics

EASY

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

The specific heat of water

= 4200 J

{kg}^{- 1} K^{- 1}

and the latent heat of ice

= 3.4 \times 10^{5} J

{kg}^{- 1}

100 g

of ice at

0^{o} C

is placed in

200 g

of water at

25^{o} C

. The amount of ice that will melt as the temperature of water reaches

0^{o} C

is close to (in grams)

MEDIUM

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

Name the physical quantity which is measured in calories. How is calorie related to the SI unit of that quantity?

EASY

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

A calorimeter of water equivalent

20 g

contains

180 g

of water at

25 ° C

{}^{'}m^{'}

' grams of steam at

100 ° C

is mixed in it till the temperature of the mixture is

31 ° C

. The value of

m

is close to (Latent heat of water

= 540 cal g^{- 1}

, specific heat of water

= 1 cal g^{- 1 °} C^{- 1}

)

MEDIUM

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

Steam at

100 ° C

is passed into

1.1 kg

of water contained in a calorimoter of water equivalent to

0.2 kg

15 ° C

till the temperature of the calorimeter and its contents rises to

80 ° C

. The mass of steam condensed (in

kg

) is

EASY

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

Two moles of oxygen is mixed with eight moles of helium. The effective specific heat of the mixture at constant volume is

EASY

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

The specific heat capacity of body depends on

MEDIUM

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

The specific heat capacity of a substance

A

3, 800 J {kg}^{- 1} K^{- 1}

and that of a substance

B

400 J {kg}^{- 1} K^{- 1}

. Which of the two substances is a good conductor of heat? Give a reason for your answer.

EASY

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

200 g

water is heated from

40^{o} C

60^{o} C

. Ignoring the slight expansion of water, the change in its internal energy is close to (Given specific heat of water

= 4184

J {kg}^{- 1} K^{- 1}

HARD

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

The figure below shows the variation of specific heat capacity ( $C$ ) of a solid as a function of temperature ( $T$ ). The temperature is increased continuously from $0$ to $500 K$ at a constant rate. Ignoring any volume change, the following statement (s) is (are) correct to a reasonable approximation.

Question Image

MEDIUM

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

Water of volume 2 L in a closed container is heated with a coil of 1 kW. While water is heated, the container loses energy at a rate of 160 J/s. In how much time will the temperature of water rise from 27^oC to 77^oC ? (Specific heat of water is 4.2 kJ/kg and that of the container is negligible).

HARD

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

A water cooler of storage capacity

120

litres can cool water at constant rate of

P

W

. In a closed circulation system (as shown schematically in the figure), the water from the cooler is used to cool an external device that generates constantly

3

kW

of heat (thermal load). The temperature of water fed into the device can not exceed

30^{o} C

and the entire stored

120

litres of water is initially cooled to

10^{o} C

. The entire system is thermally insulated. The minimum value of

P

(in

W

) for which the device can be operated for

3

hours is:

(Specific heat of water is

4.2 kJ

k g^{- 1} K^{- 1}

and the density of water is

1000 kg m^{- 3}

)

MEDIUM

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

An experiment takes

10 \min

to raise the temperature of water in a container from

0^{o} C

100^{o} C

and another

55 \min

to convert it totally into steam by a heater supplying heat at a uniform rate. Neglecting the specific heat of the container and taking specific heat of the water to be

1 cal {(g^{\circ} C)}^{- 1}

, the heat of vaporization according to this experiment will come out to be:

EASY

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

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

MEDIUM

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

The triple-point of water is a standard fixed point in modern thermometry. Why? What is wrong in taking the melting point of ice and the boiling point of water as standard fixed points (as was originally done in the Celsius scale) ?

MEDIUM

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

What do you mean by the change of state? Write the flow chart showing the complete cycle of change of state.

EASY

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

Is there any relationship of latent heat with the regelation?

MEDIUM

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

What is regelation? How can we say that water is neutral?

EASY

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

A liquid can change into vapour state at a fixed temperature. Name the process involved in the above case.

MEDIUM

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

Represent the union of two sets by Venn diagram for each of the following.

$X = {x | x$ is a prime number between $80$ and $100}$

$Y = {y | y$ is an odd number between $90$ and $100}$

EASY

Physics>Heat and Thermodynamics>Thermal Physics>Specific Heat Capacity and Specific Latent Heat

Are freezing point and melting point same with respect to change of state ? Comment.

When a substance melts, the required energy is called a specific latent heat of vaporisation.

Important Questions on Thermal Physics

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