General Science 7th Class Chapter 10 Heat and Temperature Solved Exercise

General Science

7th Class

Chapter 10

Heat and Temperature

Questions

10.1 Encircle the correct option.

1. The degree of hotness or coldness is called:

a. thermal contraction        b. thermal expansion        c. temperature        d. heat

2. The bulb of the thermometer is filled with:

a. oil        b. alcohol        c. water        d. salt

3. Centigrade scale is also called:

a. Fahrenheit scale        b. Kelvin scale        c. Absolute scale        d. Celsius scale

4. The temperature of boiling water in centigrade scale is:

a. 0˚ C       b. 32˚ C        c. 37˚ C        d. 100˚ C

5. The temperature of melting ice in Fahrenheit scale is

a. 0˚ F       b. 32˚ F        c. 100˚ F        d. 212˚ F

6. When a 10 cm iron rod is heated to high temperature:

a. its volume decreases        b. its volume increases

c. its density remains the same        d. none of these

7. The average energy due to movement of molecules in a substance is called:

a. potential energy        b. electric energy        c. kinetic energy        d. chemical energy

8. The energy that transfers from one object to another due to the temperature difference is called:

a. atomic energy        b. heat energy        c. light energy        d. sound energy

9. The gaps are left after every few minutes in the railway tracks, so that:

a. they cannot be de-tracked in summer due to expansion

b. they cannot be de-tracked in winter due to expansion

c. they cannot be de-tracked in summer due to contraction

d. they cannot be de-tracked at night due to contraction

10. The rise of liquid in the thermometer is due to:

a. evaporation        b. contraction        c. expansion        d. sublimation

11. The contraction of the objects on cooling is due to:

a. reduction in size of the particles        b. increase in size of the particles

c. increase in inter particle distances        d. decrease in inter particle distances

12. An empty steel container is sealed and heated, which of the following properties of the gas is likely to increase?

a. mass        b. pressure        c. volume        d. density

10.2 Give short answers.

1. Define heat.

2. Name three modes of heat transfer.

3. Which two temperatures are the base of Celsius and Fahrenheit temperature scales?

4. Give five examples of good conductors of heat.

5. Give five examples of bad conductors of heat.

1. Define heat.

Ans.

Heat is the measure of thermal energy of a substance. It is the total kinetic energy of all the particles of a substance.

2. Name three modes of heat transfer.

Ans.

Three modes of heat transfer are the following:

1. Conduction        2. Convection        3. Radiation

3. Which two temperatures are the base of Celsius and Fahrenheit temperature scales?

Ans.

Melting point and boiling point of water are two temperatures which are base of temperature scales.

4. Give five examples of good conductors of heat.

Ans.

Five good conductors of heat are Iron, Copper, Silver, Aluminum and Gold.

5. Give five examples of bad conductors of heat.

Ans.

Five bad conductors are wood, rubber, glass, mica and cotton.