Heat Transfer

Q.

A body increases its temperature by____

1. Transmitted heat energy

2. All of the above

3. Reflected heat energy

4. Absorbed heat energy

Q.

Which of the following energy conversion takes place in an electric heater?

1. Electrical energy is converted to heat energy.

2. Chemical energy is converted to electrical energy

3. Chemical energy is converted to heat energy

4. Heat energy is converted to electrical energy

Q. Which of the following energy conversions take place in a torch?

1. $\text{Electrical}\to \text{Chemical}\to \text{Light}$
2. $\text{Chemical}\to \text{Electrical}\to \text{Light}$
3. $\text{Electrical}\to \text{Light}\to \text{Chemical}$
4. $\text{Light}\to \text{Chemical}\to \text{Electrical}$

Q.

Why is conduction not possible in the case of liquids and gases?

Q. A tile floor feels colder than a wooden floor when you walk on it, even when both are at same temperature. Why?

Q.

How does the movement of air take place?

Q.

How is the heat energy supplied to a liquid during boiling at a fixed temperature, utilized?

Q. What is principle of calorimetry ?

Q. (a) Why are the windows of the houses in coastal areas made to face the sea?

(b) What is a land breeze?

Q. Suppose you have three bodies A, B and C. A and B are at same temperature. When B and C are brought in contact, heat flows from C to B until flow of heat stops. What will happen when A and C are brought in contact?

1. Heat will flow from A to C.
2. Heat will flow from C to A.
3. Heat will not flow.
4. Insufficient information

Q.

Which of the following process is shown by iodine and naphthalene?

1. Melting

2. Sublimation

3. Liquefaction

4. Vapourisation

Q. A metal sheet has a circular hole cut out in middle. On application of heat, the sheet will undergo thermal expansion. Which image shows correct expansion?

1. 
2. 

Q.

No medium is required to transfer heat by the process of ____________.

Q. What is the energy conversion taking place in an electric heater?

1. Chemical energy is converted to electrical energy
2. Chemical energy is converted to heat energy
3. Heat energy is converted to electrical energy
4. Electrical energy is converted to heat energy.

Q. Assertion :The expansion produced in the matter due to absorption of heat energy is called Thermal Expansion Reason: The coefficient of linear expansion decreases with the increase of temperature.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q.

Boiling is a/an ___ phenomenon.

1. surface

2. bulk

3. atomic

4. atmospheric

Q.

When a liquid starts to boil its temperature ________________.

1. Increases

2. Decreases

3. Can either increase or decrease

4. Remains constant

Q. Which of these is true about the direction of heat flow?

Q.

When a liquid starts to boil during heating, its temperature ___.

Q. Riaz needs a box which can absorb the heat from the sun very fast but lose it very slowly. How should the outer and the inner surface of the box be coloured so that he gets the best result?

1. Outer - Black, Inner - Black
2. Outer - Silver, Inner - Silver
3. Outer - Silver, Inner - Black
4. Outer - Black, Inner - Silver

Q. Which of the following energy conversions take place in a torch?

1. $\text{Light}\to \text{Chemical}\to \text{Electrical}$
2. $\text{Electrical}\to \text{Light}\to \text{Chemical}$
3. $\text{Chemical}\to \text{Electrical}\to \text{Light}$
4. $\text{Electrical}\to \text{Chemical}\to \text{Light}$

Q. Suppose you have three bodies A, B and C. A and B are at same temperature. When B and C are brought in contact, heat flows from C to B until flow of heat stops. What will happen when A and C are brought in contact?

1. Heat will flow from C to A.
2. Heat will flow from A to C.
3. Heat will not flow.
4. Insufficient information