CBSE Science Practice Paper Set V

1. The refractive index of water and glass are 1.33 and 1.5 respectively. Find the refractive index of water with respect to glass. 1


2. Give one example of slow reaction. 1


3. What is the role of rods and cones in human eye ? 1


4. Write reaction of methanal with HCN. 1


5. Why do we make conductors of heating devices made of an alloy instead of a pure metal ? 1


6. What happens when calcium hydroxide is treated with chlorine gas ? Give chemical equation. 2


7. How much solar energy is received in 1 m area in one hour. Given : Solar constant is 1.4 kW per square metre ? 2


8. What are primary colours and complementary colours. Give two examples each. 2


9. Calculate pH of a solution having [H+] = 1.0 x l0-4 mol L-1. State whether the solution is acidic or basic.


OR

N2O4(g)=2NO2, the concentration of [N2O4] = 4.0 x 10-2 mol L-1; [NO2] = 1.5 x 10-2 mol L-1 at equilibrium. Calculate the value of equilibrium constant, 2


10. Who first found that current can produce magnetic field ? Write the Right hand grip rule to find the direction of magnetic field. 2


11. A white powdered solid, when added to water produces a hissing sound. Identify the compound. How does this compound react with moist hydrogen chloride gas ? Write the chemical equation. Give two uses of same compound. 3


12. What is the source of Geothermal energy ? Name the places where this energy is tapped. 3


13. Metals are electropositive in nature, why ? How are most reactive metals obtained from their ore ? Name the method and give one example of such metal.


OR

What is meant by refining of petroleum ? Name the process used for refining. Give name and uses of products obtained at 180°C and 260°C. 3


14. What do you mean by summer and winter solstice ? 3


15. Docs the nature of image formed by a concave mirror depend on the position of an object ? Show this with the help of two ray diagrams. 3


16. How will you prepare ammonia gas in the laboratory ? Draw a labelled diagram and write the chemical reaction involved. Give one chemical test for detecting presence of NH~ gas. 3


17. Complete the following reactions :

(i) CH3COOC2H5+NaOH—————>
(ii) CH3CH2OH
CrO3in/CH3COOH





18. (i) What is Myopia ? How can you correct it ? Draw diagrams to show defective and corrected eye. (ii) A short sighted person cannot see objects beyond 100 cm. How can you correct it to enable him to see an object at 150 cm ?


OR

(i) What is Hypermetropia ? How can you correct it ? Draw diagrams to show defective and corrective eye.
(ii) A farsighted woman has a near point of 1.5 m. Calculate the focal length of the lenses for her eye glasses, so that she can read a book held at 25 cm. 3+2


19. What is meant by refining of metals ? Explain three processes for refining of metals. Which method is used for refining volatile metals ?


OR

{a) What are non-metals ? Give two physical and two chemical properties of non-metals. (b) What happens when
(i) Hydrogen reacts with heated CuO ;
(ii) Sulphur dioxide reacts with lime water. 5


20. How can we extract aluminium metal from Bauxite ore. Explain purification of bauxite with the help of chemical reactions and extraction with the help of neat and labelled diagram. 5


Section - B

21. Name the gland which produces (a) FSH. (b) Oxytocin. 1


22. Give two examples of organisms which can regenerate from small part of their body. 1


23. What are analogous organs ? Give one example. 1


24. What do you mean by National Parks and Sanctuaries ? 2


25. Define heart beat and heart sound. 2


26. Discuss the importance of vegetative propagation.

OR

‘Grafting is a common method of obtaining a superior plant from two different plants’ ? Explain. 3


27. Write note on ‘Chemical Control in Animals’. 3


28. What do you mean by water table ? What happens if water table in a region falls ? 3


29. Differentiate between lymphatic capillaries and blood capillaries. 3


30. Explain with a diagram the structure of a chromosome. Write the features of eukaryotic and prokaryotic chromosome. 5