Hot and Cold

Q. Is mercury a good conductor of heat?

Q.

Why do hot air goes up and cool air comes down explain it with video

Q.

How does the sea get hot at night?

Q.

Temperature is not a physical quantity.

1. Stress
2. Young's modulus of elasticity

Q.

How are heat and kinetic energy related?

Q. An empty glass bottle is fitted with a narrow tube at its mouth. The open end of the tube is kept in a beaker containing water. When the bottle is heated, bubbles of air are seen escaping into the water. Explain the reason.

Q.

After holding a pack of ice in your hand for some time, put your hand in water at room temperature. Your hand would now feel:

1. Colder

2. Same as before

3. No sensation

4. Warmer

Q. Conduction of heat takes place through solids where the molecules are closely packed.Then why does a rubber or a glass have low conductivity of heat and are among the best insulators? They are also solids. They also have molecules which are closely packed?

Q.

During the melting of a solid, there is no change in the kinetic energy of molecules.

1. True
2. False

Q. Which temperature scale is used in the metric system?

1. Metre
2. Kilogram
3. Fahrenheit
4. Degree Celsius

Q.

Name the mode of transfer of heat from one particle to another in solids.

Q.

The heat which comes out of the hot object is called _____________heat.

Q.

What is hotness of a body?

1. It is an absolute value

2. It is a relative value

3. It depends on the scale of the temperature used

4. It cannot be measured

Q. The process by which transfer of heat takes place by the actual movement of particles from one part of the body to another part is called ___________.

1. conduction
2. convection
3. radiation
4. thermometer

Q. Which of the following statements are correct regarding warm and cold air?
1. Warm air is lighter than cold air.
2. Warm air rises up.
3. Cold air sinks down.
4. Cold air is lighter than warm air.

1. 1 and 2 only
2. 1, 2, 3 only
3. 3 and 4 only
4. 1, 2, 3 and 4

Q.

Copper and steel are ________ conductors of heat.

Q. A reliable measure of the degree of hotness or coldness of a body is called its_________

1. mass
2. volume
3. temperature
4. potential energy

Q. Which of the following are the best matchings of column-I and column-II?
Column - I Column - II
(A) Conduction (p) Black surface
(B) Convection (q) Vacuum
(C) Radiation (r) Air
(D) Absorption (s) Solid medium

1. A→ (r), B→ (s), C→ (p), D→ (q)
2. A→ (r), B→ (s), C→ (p), D→ (q)
3. A→ (s), B→ (r), C→ (q), D→ (p)
4. A→ (s), B→ (p), C→ (r), D→ (q)

Q.

The higher the temperature of the surface, the greater is the amount of radiation emitted.

1. True
2. False

Q. Which metal is used in a thermometer?

1. Zinc
2. Potassium
3. Lead
4. Mercury

Q. While making soup, the of the soup can be checked by our sense of touch.

1. smell
2. taste
3. hotness
4. colour

Q. Why do cooking vessels usually have copper bottoms?

1. Copper has low melting point.
2. Copper is an insulator of heat.
3. Copper is a good conductor of heat
4. Copper is cheap.

Q. In places of hot climate it is advised that the outer walls of houses be painted white. Explain.​

Q. Select the correct statement among the following.

1. Hot air is heavier than cold air.
2. Hot air is lighter than cold air.
3. Hot air occupies less volume than cold air.
4. Hot air and cold air are equally heavy.

Q. Beaker A contains hot water. Beaker B contains cold water. Beaker C contains a mixture of hot and cold water. If initially your hand is put into a beaker containing ice, then putting your hand in which of the beakers A, B or C will give a sensation of warmth?

1. A
2. B
3. C
4. All of the above.

Q.

Can you classify the following bodies as hot or cold? Body, A furnace, ice tea , tap water , base of an iron , pencil , molten wax

Q. Explain an example where heat is transferred by all three means

Q. Which of the following statements are correct regarding warm and cold air?
1. Warm air is lighter than cold air.
2. Warm air rises up.
3. Cold air sinks down.
4. Cold air is lighter than warm air.

1. 1 and 2 only
2. 1, 2, 3 only
3. 3 and 4 only
4. 1, 2, 3 and 4

Q. When two bodies at different temperatures are placed in thermal contact with each other, heat flows from the body at a higher temperature until they both acquire the same temperature. Assuming that there is no loss of heat to the surroundings, then:

1. The heat gained by the hotter body will be less than the heat lost by the colder body
2. The heat gained by the hotter body will be equal to the heat lost by the colder body
3. The heat lost by the hotter body will be equal to the heat gained by the colder body.
4. The heat gained by the hotter body will be greater than the heat lost by the colder body

Q. Iron glows in red colour when it is heated to very high temperature. The reason for this is :

1. All metals glow in red colour when heated
2. Heat energy is being converted into light energy
3. Heat we supply consumes red colour at high temperature
4. Mechanical energy is being converted into heat energy