#### Heat Model Questions

9th Standard

Reg.No. :
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Science

Time : 01:00:00 Hrs
Total Marks : 50
5 x 1 = 5
1. Calorie is the unit of

(a)

heat

(b)

work

(c)

temperature

(d)

food

2. Two cylinders of equal height and radius are made of copper and aluminium. Which of them conducts heat faster?

(a)

Copper rod

(b)

Aluminium rod

(c)

Both of them

(d)

None of them

3. 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

4. The temperature at which a liquid gets converted into its vapour state is called its________

(a)

melting point

(b)

boiling point

(c)

dew point

(d)

freezing point

5. Which one of the following scales has lower fixed point at 0°C?

(a)

Kelvin scale

(b)

Fahrenheit scale

(c)

Celsius scale

(d)

All of these

6. 5 x 1 = 5
7. The fastest mode of heat transfer is______________

()

8. During day time, air blows from________________to_____________

()

sea to land

9. Liquids and gases are generally_________conductors of heat.

()

poor

10. ______________is greater for liquids than for solids and maximum in case of gases.

()

Expansion

11. When heat energy is added to a substance, the kinetic energy of its particles _________ and so the particles many at higher speed.

()

increase

12. 5 x 1 = 5
13. Heat

14. (1)

Heat gained or lost in change of state without any change in temperature

15. m x L

16. (2)

Heat gained or lost when there is no change of state

17. m x s x t

18. (3)

Form of energy

19. J / Kg

20. (4)

4.2 J/g0C

21. Specific heat capacity of water

22. (5)

SI unit of specific latent heat

5 x 2 = 10
23. 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)

24. Heat gained by a body depends upon which factors?

25. Define one calorie.

26. What is the relation between calorie and Joule?

27. What is the minimum possible temperature? Is there also a maximum possible temperature?

28. 5 x 3 = 15
29. Define conduction

30. Why are burns caused by steam more painful than those caused by boiling water at the same temperature?

31. What is the amount of heat required to raise the temperature of 5 kg of iron from 30°C to 130°C? Specific heat capacity of iron = 483 Jkg-1C-1.

32. Calculate the amount of heat required to convert 200g of ice at 00C into water at 00C Specific latent heat of fusion of ice = 336 Jg-1

33. How much boiling water at 100ºC is needed to melt 2kg of ice so that the mixture which is all water is at 0ºC?

34. 2 x 5 = 10
35. Give the difference between heat and temperature.

36. Give some practical applications of specific latent heat of ice.