" /> -->

#### Heat Book Back Questions

9th Standard

Reg.No. :
•
•
•
•
•
•

Science

Time : 00:45:00 Hrs
Total Marks : 30
3 x 1 = 3
1. Calorie is the unit of

(a)

heat

(b)

work

(c)

temperature

(d)

food

2. In which mode of transfer of heat, molecules pass on heat energy to neighbouring molecules without actually moving from their positions?

(a)

(b)

Conduction

(c)

Convection

(d)

Both Band C

3. A device in which the loss of heat due to conduction, convection and radiation is minimized is

(a)

Solar cell

(b)

Solar cooker

(c)

Thermometer

(d)

4. 4 x 1 = 4
5. The fastest mode of heat transfer is______________

()

6. During day time, air blows from________________to_____________

()

sea to land

7. Liquids and gases are generally_________conductors of heat.

()

poor

8. The fixed temperature at which matter changes state from solid to liquid is called

()

melting point

9. 2 x 2 = 4
10. What is the heat in joules required to raise the temperature of 25 grams of water from 0ºC to 100ºC? What is the heat in Calories?
(Specific heat of water = 4.18 J/gºC)

11. How much heat energy is required to change 2 kg of ice at 0ºC into water at 20ºC? (Specific latent heat of fusion of water = 3,34,000J/kg, Specific heat capacity of water = 4200JKg-1K-1).

12. 3 x 3 = 9
13. What is specific heat capacity?

14. Define thermal capacity.

15. Calculate the heat energy required to raise the temperature of 2kg of water from 10ºC to 50ºC. Specific heat capacity of water is 4200 JKg-1 K-1.

16. 2 x 5 = 10
17. Explain convection in daily life.

18. How can you experimentally prove that water is a bad conductor of heat? How is it possible to heat water easily while cooking.