Practical Application of Thermal Expansion

Q.

Why is a small gap left behind the walls while mounting a girder for roofing? Explain.

Q.

Differentiate between Linear and Cubical expansion

Q.

When we heat kerosene oil in a container, its level rises. This is an example of

1. Surface expansion

2. None of the above

3. Linear expansion

4. Volume expansion

Q.

A wheel and axle is a simple machine made up of two identical cylinders.

1. True
2. False

Q.

Cubical expansion refers to an increase in _________.

Q.

On heating a bimetallic strip made from brass and iron, the brass strip expands more. $({\alpha }_{brass}>{\alpha }_{iron})$

1. False

2. True

Q.

The girders supporting the bridge are fixed in the walls of the pillars.

1. True

2. False

Q.

In liquids, heat is transferred due to vibration of the molecule.

1. True
2. False

Q.

The extent of expansion is different in different solids.

1. True
2. False

Q.

A solid transfers heat to another solid in contact with it by the process of ____________.

Q.

Give reason a gap is left between two section of rail track.

Q.

Why are gaps left between successive rails on a railway track?

Q. Electrical wires stretch and sag during summer, because it expands on heating.

1. True
2. False

Q. While laying the railway tracks, a small gap is left between the successive lengths of rail.

1. To restrict thermal expansion
2. To compensate for the thermal expansion
3. To compensate for the thermal contraction
4. To avoid thermal stain

Q.

Small gaps are left between railway lines because:

1. rails of very long lengths are not available.

2. expansion of rails during summer

3. contraction of rails during summer

4. both (b) and (c)

Q.

Why are small gaps left in between the rails?

Q. Why are gaps left between lengths of railway tracks?

Q.

Give reason why gaps are provided between two successive lengths of rail?

Q.

Solids expand ________[more/less] than liquids.

Q.

Which of the following experiences only cubical expansion on heating?

1. Solids

2. Liquids

3. Gases

4. All of the above

Q.

Write true or false for each statement.

1. Medium is necessary for the transfer of heat by radiation.
2. Solids expand the least and the gases expand the most on being heated.
3. Water is a bad conductor of heat.
4. Land and sea breezes are the convection currents of cold and warm air.
5. Black surfaces are the poor absorbers of heat radiations.

[5 marks]

Q.

The girders supporting the bridge are fixed in the walls of the pillars.

1. True

2. False