SAMPLE PAPER/ MODEL TEST PAPER CBSE SA 2 2012
SECTION – A
2. Write two advantages of sexual reproduction over asexual reproduction?
3. What is regeneration? State a reason why a more complex organism cannot give rise to new individuals through this method.
4. What happens when a small piece of sodium is dropped into ethanol?
5. Which compounds are responsible for the depletion of ozone layer?
6. Why is DNA copying an essential part of the process of reproduction?
7. Why are bacteria and fungi called decomposes? Give any one advantage of decomposes to the environment.
8. Suggest any two changes that you would like to be incorporated in the life – style of students of your age to move towards a sustainable use of available resources.
9. An old person is unable to see clearly nearby objects as was as distant objects.
(a) What defect of vision is he suffering form?
(b) What kind of lens will be required to see clearly the nearby as well as distant objects?
10. List any two advantages of water harvesting.
11. Name the male and female gametes in animals. What is fertilization and where does it take place in human females?
12. (a) Distinguish between esterification and saponification reactions of organic compounds.
(b) With a labeled diagram describe an activity to show the formation of an ester.
13. (a) What is vinegar?
(b) Describe with a chemical equation, what happens when sodium hydrogen carbonate reacts with ethanoic acid.
14. (a) What is meant by periodicity in properties of elements with reference to the periodic table?
(b) Why do all the tendency to gain electrons change as we go from left to right across a period? Why?
15. What is meant by exploitation of resources with short term aims? List its four advantages.
16. A student focused the image of a candle flame on a white screen by placing the flame at various distances from a convex lens. He noted his observations in the following table:
|Distance of the flame from the lens (cm)||Distance of the screen from the lens (cm)|
Analyse the above table and answer the following questions:
(a) What is the focal length of the convex lens?
(b) Which set of observations is incorrect and why?
17. What is dam? Write two main advantages and two ill- effects of constructing a big dam.
18. (a) What is a ‘homologous series’ of substances?
(b) In an organic compound, which parts largely determine its physical and chemical properties?
(c) Write a chemical equation to represent the reaction of ethanol with acidified solution of potassium dichromate.
19. Soap does not work well with hard water. Name the class of compounds. Example in brief the mechanism of its cleansing action when used in hard water.
20. (a) What is dispersion of white light? What is the cause of such dispersion? Draw a diagram to show the dispersion of white light by a glass prism.
(b) A glass prism is able to produce a spectrum when white light passes through it but a glass slab does not produce any spectrum. Explain why it is so.
21. Name the part of our eyes that helps us to focus near and distant objects in quick succession.
22. The outer surface of a hollow sphere of aluminum of radius 50 cm is to be used as a mirror. What will be the focal length of this mirror? What type of spherical mirror will it provide?
23. What is myopia (near – sightedness)? Draw a ray diagram to show how it can be corrected using a lens.
24. What is the nature of the image formed by a concave mirror if the magnification produced by the is + 3 ?
25. Between which two points of a concave mirror should an object be placed to obtain a magnification of -3?
26. In an experiment on tracing the path of a ray of light through a rectangular glass slab, four students A, B, C, D used the following value of angle of incidence and the distance between the feet of two pins (fixed on the incident ray):
(A) 30 degree, 45 degree, 60 degree) and 1 cm (B) (30 degree, 45 degree, 60 degree) and 6 cm (c) (20 degree, 50 degree, 80degree) and 10 cm
(d) ( 20 degree 50 degree, 80 degree ) and 15 cm
Out of these the best choice is that of students
(a) A (b) B (c) C (d) D
27. When blue litmus solution is added to a solution of acetic acid, it turns red. What change(s) will be observed when a few drops of concentrated NaoH is added to it?
(a) The mixture turns blue. (b) The mixture becomes colorless.
(c) The mixture remains red. (C) None of the above.
28. A student put five raisins each in two nickers A and B . Beaker A contained 50 ml of distilled water and beaker B had 50 ml of saturated sugar solution. After some time the student would observe that
(a) raisins in beaker A were more swollen than those in beaker B.
(b) raisins in beaker B were more swollen than those in beaker A.
(c) raisins in both beakers A and B were equally swollen.
(d) rains in beaker A did not swell up at all.
29. On adding acetic acid to solid sodium carbonate, a student observes the liberation of a
(a) greenish yellow gas with a pungent smell.
(b) Colourless and odourless gas.
(c) Yellow coloured, odourless gas.
(d) Colourless gas with smell of rotten eggs.
30. A student is to find the focal length of a (i) concave mirror, (ii) convex lens by using a distant object. He will observe that the screen is on the same side as the object
(a) in both the cases (b) in neither of the two cases
(c) in case (i) but not in case (ii) (d) in case (ii)but not is case (i)
31. (a) why do we classify elements?
(b) Would you place the two isotopes of chlorine, CI – 35 and CI – 37 in different slots because of their different atomic masses or in the same because their chemical properties are the same? Justify your answer.
(c) why did Mendeleev leave some gaps in his periodic Table?
(d) What were the two criteria used by Mendeleev in creating his periodic Table?
(e) In Mendeleev’s Periodic Table, Why was there no mention of Noble gases like Helium, Neon and Argon?
32. Name a form of acetic acid which is used for pickling salads:
(a) Vinegar (b) Methanoic acid (c) Benzoic acid (d) Sodium acetate
33. A student dissolved 2 g of sugar in 20 ml of distilled water in beaker A. He dissolved 5g of in 50 ml distilled water in beaker B. Then he dropped a few raisins in each beaker. After two hours, he found the raisins have
(a) swollen in A and shrunken in B
(b) shrunken in A and swollen in B
(c) swollen in both
(d) shrunken in both
34. A ray of light traveling in a medium falls normally on the surface of another medium. While entering the second medium, it
(a) goes straight into the second medium
(b) bends away from the normal
(c) bends towards the normal
(d) does not enter the normal
35. A student was given the following suggestion, by his fellow students for performing the experiment on finding the focal length of convex lens.
(i) Select an object very far away from the laboratory window.
(ii) Keep all lights of the lab on.
(iii) Select a well illuminated object far, but not very far, from the laboratory window.
(iv) Place the lens between the object and the lens.
(v) Place the screen between the objects and the lens.
(vi) Obtain the sharpest image of the object on the screen.
He can perform the experiment better following the suggestions:
(a) (i), (iv), (vi) (b) (ii), (iii), (v) (c) (iii), (vi), (ii) (d) (iv), (vi), (ii)
36. The correct labelling of the figure is:
(a) P: Rachis; Q Pinnules;
R: Raizome; S: Adventitious roots
(b) P: Branchi; Q Leaflets; R: Thallus; S: Roots
(c) P: Rachis; Leaves; R: Thallus; Root
(d) P: Mid rib; Q: Compound leaves;
R: Stem; S: Root hairs
37. Some raisins weighed 10 gm before they were placed in water for four hours. The raisins were then removed, wiped and weighed again and weighed again. Their weight was now found to be 12.5 gm.
(a) 2.5% (b) 5% (c) 12.5% (d) 25%
38. While performing an experiment on verifying the laws of reflection of sound, the’ reflected sound’ can be detected better by keeping one ear.
(a) near the end of the tube and keeping one ear closed.
(b) near the end of the tube and keeping the other ear opens.
(c) at about 5 cm from the end of the tube and keeping the other ear closed.
(d) at about 5 cm from the end of the tube and keeping the other ear open.
CBSE SA (2) 2012 Sample Paper / Model Test Paper