CBSE Science Practice Pape Set VI

Section - A

1. Relate the incident and emergent angle of light in a glass slab. 1
 

2. What is meant by exothermic process ? Give one example. 1
 

3. What is meant by catalyst ? 1
 

4. If a wire of resistance R, length / made of material of resistivity p is cut into two equal parts, find the resistivity and resistance of the two pieces. 1
 
5. Define pH. 1
 

6. Name two materials used in the manufacture of solar cells. What is the efficiency of modern solar cells? 2
 

7. Out of the two fuels C4H10 and C4H9OH, which one is expected to have a higher calorific value and why? 2
 

8. Draw the ray diagram to show how a simple microscope magnifies.

OR

State Faraday’s law of electrolysis. 2
 

9. Give two important properties of steel. 2
 

10. Equilibrium constants for the reactions given below are provided in the right hand side at 298 K. 



In which case, formation of products will be more favourable ? 2
 

11. What is fuse wire ? Why do we need it ? How is it connected in electric networks ? 3
 

12. Write chemical equations to show what happens when :
(i) Ammonia is passed over heated copper oxide.
(ii) CO is pased over heated ferric oxide. 
(iii) Sulphur powder is heated with concentrated HNO3.

OR

How will you prepare sulphur dioxide gas in the laboratory ? Draw a neat and labelled diagram and write chemical reaction involved. Give two physical properties of SO2. 3
 

13. Write the mirror formula with proper sign convention. A convex mirror u^ed on an automobilehas radius of curvature of 3.00 m. Find the position and nature of image of a bus at a distance of 5.0 m from the mirror.

OR

A concave lens of focal length 10 cm is given. An ant 2 cm long stands vertically on the principal axis at a distance of 15 cm. Find the position and nature of image formed writing the lens formula, with proper sign convention. (1/,+72+2 = 3)
 

14. Define rate of reaction. Calculate the rate of reaction of ion Cis-Platin with water between t1 =20 minutes and t2 = 40 minutes from the following table : 3



15. Write the basic principle and working of an electric motor. 3
 

16. Write a short note on the layers of our Earth. 3
 

17. Calculate the altitude for a earth’s satellite to be a geostationary satellite. 3
 

18. What are galaxies and constellations’? Write two differences between them. What is the name and shape of our galaxy ? Write about asteroids seen in our .solar system. 5
 

19. What is chemical formula of ethyl alcohol ? How is it prepared from sugarcane ? Name the process. Give chemical reactions involved. Give harmful effects of drinking alcohol.


OR

Complete the following reactions :


20. Explain with a neat labelled ray diagram, the working of an Astronomical telescope ? 5
 

Section - B

21. Name one gland in human body which secretes digestive enzyme as well as hormone. 1
 

22. Name the protein which gives red colour to the blood. 1
 

23. Why is pituitary gland considered as a master gland ? 1
 

24. Explain the terms (a) Zoophily and (b) Anemophily. 2
 

25. What are environmental laws ? 2
 

26. Explain the sex determination mechanism in human beings. 3
 

27. What is Greenhouse effect ? Name two green house gases. What will happen to our earth if these gases are absent in the atmosphere ? 3
 

28. Name the products of photosynthesis which play a vital role in your daily life. 3
 

29. Name the various organic and inorganic components found in plasma of the blood. 3
 

30. What are the various parts of a flower ? Explain with the help of a diagram the reproductive parts of a flower.

OR

(i) Explain briefly the various methods of artificial vegetation. (ii) What is tissue culture ? Give two advantages of vegetative propagation. 2+3