Conduction

Q. Why do woollen clothes keep us warm in winter?

1. Wool is a good conductor of heat.
2. Wool traps heat effectively between its layers.
3. Wool is a bad conductor of heat.
4. Wool produces its own heat from its layers.

Q.

What is the process of water changing into ice called?

1. Boiling

2. Melting

3. Condensation

4. Freezing

Q.

The change in state from solid to gas is known as:

1. melting

2. boiling

3. freezing

4. sublimation

Q.

Heat supplied to a solid changes it into liquid. What is this change in phase called?

Q.

How does heating and cooling affect the state of a substance?

Q. In which among the following, heat transfer happens through conduction:

1. All of the above.
2. Solids
3. Liquids
4. Gases

Q.

The changing of a liquid into gas on heating, is called___________.

1. melting

2. boiling

3. vaporisation

4. condensation

Q. Which of the following substance is most suitable as a handle for a cooking utensil?

1. Iron
2. Wood
3. Copper
4. Aluminium

Q.

The car radiator cools the engine by circulating _______ around it.

Q.

The temperature at which a liquid boils and changes rapidly into a gas is called its boiling point.

1. True
2. False

Q.

At the melting point, water exists in the:

1. Solid state

2. Liquid state

3. The solid and gaseous state

4. Solid and liquid state

Q. Woolen clothes have _____ that help in insulation.

1. thin fibres
2. packets of water
3. packets of trapped air
4. heating coils

Q. Which of the following is true with respect to conduction?

1. Atoms move from hot region to cold region.
2. Atoms vibrate about their mean positions to transfer energy.
3. Atoms are not required to transfer energy.
4. Heat energy gets transferred instantaneously.

Q. The pair of physical quantities that have same dimensions are:
a) Reynold's number and coefficient of friction
b) Latent heat and gravitational potential
c) Curie and frequency of light wave
d) Planck constant and torque

1. b and c are correct
2. a and b are correct
3. all are correct
4. a, b and c are correct

Q. The gap in between the walls of a thermos flask reduces the heat transfer by:

1. Conduction
2. Convection
3. Radiation
4. Both conduction and convection.

Q.

Define the following process involved in the change of state of a substance- freezing

Q.

43 The coat worn by warriors is made up of metal. What would happen, if these coats are made up of fibre?

Q.

The conversion of solid into liquid is called sublimation.

1. True
2. False

Q.

Rapid conversion of liquid into its gaseous state is called

1. Melting

2. Boiling

3. Evaporation

4. Sublimation

Q.

The changing of solid into liquid on heating, is called___________.

1. melting

2. fusion

3. both (A) and (B)

4. none of these

Q.

Ventilators are made close to the ceilings.

Q.

Differentiate between conductors and insulators.

Q.

The conversion of ice into water is an example of _________

Choose the correct answer from the following.

1. Melting

2. Freezing

3. Condensation

4. Sublimation

Q.

Define: Melting

Q.

At the melting point, the temperature remains ______________.

Q.

List any three effects of heat.

Q. Suggest a way to remove a tight glass stopper from a bottle

Q.

The fastest method of heat transfer from a hot body to a cold body is

1. conduction

2. convection

3. radiation

4. none

Q.

The change of state of a substance from liquid to solid ___________.