CBSE Science Practice Paper Set X

Section - B

1. What is the contribution of Edwin Hubble to space science ? 1
 

2. What is meant by instantaneous rate of reaction ? 1
 

3. What are raw materials used for manufacture of glass ? 1
 

4. Name the substance used as (i) a moderator and (ii) a coolant in a nuclear reactor. 1
 

5. Write structural formula of ethanoic acid. 1
 

6. Write the conditions under which light undergoes total internal reflection. 2
 

7. Name an alloy used in the making of permanent magnets. Give two uses of these magnets. 2
 

8. What is corrosion ? Give conditions in which rusting of iron takes place. 2
 

9. How is bleaching powder manufactured ? Give one use of bleaching powder. 2
 

10. A 40W, 220V bulb is connected to 110V supply, find (i) Current flowing in the filament, (ii) Power consumed.


OR

A 60W, 220V bulb is connected to a 220V supply, find
(i) current (ii) Energy consumed in 1 hr. 2
 

11. State two major objectives of space research programme in India also give its focal length. 3
 

12. Write the nature of image formed by a plane mirror. 3
 

13. Why is charcoal considered a better fuel than wood ? What are disadvantages of converted wood into charcoal ?

OR

What are amalgams ? Give two examples. Give two uses of amalgams. 3
 

14. What is a fuse wire ? Name the materials used in making the fuse wire. How it is connected in the house ? How the connection differs from the normal connection used for other devices?

OR

What is solar cooker ? What is the range of temperature produced in 2-3 hours of use ? Give two
limitations and advantages. 3
 

15. Discuss refraction in a glass slab and hence write the basic laws of refraction. 3

16. Explain the working of a dry cell with a neat diagram. 3

17. At 298 K, the equilibrium concentration of the reactants and products for the reaction :

H₂(g) +I₂ (g)= 2HI (g) are as follows :
[HI] = 0.49 M, [H₂] = 0.080 M, [I₂] = 0.060 M.
Calculate the equilibrium constant at this temperature. 3

18. What are enzymes ? Name the enzymes required for fermentation of sugarcane to ethanol. Which gas is evolved during the process of fermentation ? How is ethanol prepared from ethene ? Give two uses of ethanol. 3

19. Derive Len’s formula. Define magnification. Relate HI, v,/for a lens. Use it to find the position of an Image formed by a convex lent of focal length 20 cm and magnified 2 times.

OR

Derive mirror formula. Define magnification. Relate m , v and/for a concave mirror. Use it to find the
position of an image formed by a concave mirror of focal length 20 cm and magnified 2 times. 3+2

20. Write three physical and three chemical properties of methanoi. Write chemical reactions involved. 5

Section - B

21. What is the source of free oxygen given out by the plants ? 1

22. Name a phytohormone which is a growth inhibitor. 1

23. What is self-pollination and cross-pollination ? 1

24. Write short notes on : (a) tubectomy and (b) vasectomy. 2

25. Explain why there are changes of accumulation of harmful chemicals in the body of human beings. 2

26. Give the difference between point sources and non-point sources. 3

27. Write the functions of (a) Testis, {b) Ovaries, © Epididymis. 3

28. What are the various methods of vegetative propagation ? Discuss any one method. 3

29. Why is the DNA molecule compared to a spiralling staircase ? Which three components make up the nucleotide ? 3

30. Draw a well-labelled diagram to explain the excretory system of man.

OR

Draw a well-labelled diagram to explain the respiratory system of man. 5