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Important Instructions for the

School Principal

(Not to be printed with the question paper)

1) This question paper is strictly meant for the use in School Based Summative Assessment-II, March-2012 only. This question paper is not to be used for any other purpose except

mentioned above under any circumstances.

2) The intellectual material contained in the question paper is the exclusive property ofCentral Board of Secondary Education and no one including the user school is allowed to

publish, print or convey (by any means) to any person not authorised by the Board in this

regard.

3) The School Principal is responsible for the safe custody of the question paper or any othermaterial sent by the Central Board of Secondary Education in connection with School

based SA-II, March-2012, in any form including the print-outs, compact-disc or any other

electronic form.

4) Any violation of the terms and conditions mentioned above may result in the actioncriminal or civil under the applicable laws/byelaws against the offenders/defaulters.

Note:Please ensure that these instructions are not printed with the question

paper being administered to the examinees.

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SUMMATIVE ASSESSMENT II, 2012

II, 2012

SCIENCE /

Class X / X

Time allowed : 3 hours Maximum Marks : 80

3 80General Instructions :

(i) The question paper comprises of two Sections, A and B. You are to attempt both the

sections.

(ii) All questions are compulsory.

(iii) There is no overall choice. However, internal choice has been provided in all the five

questions of five marks category. Only one option in such questions is to be attempted.

(iv) All questions of Section-A and all questions of Section-B are to be attempted separately.

(v) Question numbers 1 to 4 in Section-A are one mark questions. These are to be answered in

one word or in one sentence.

(vi) Question numbers 5 to 13 in Section-A are two marks questions. These are to be answered

in about 30 words each.

(vii) Question numbers 14 to 22 in Section-A are three marks questions. These are to be

answered in about 50 words each.

(viii) Question numbers 23 to 25 in Section-A are five marks questions. These are to be answered

in about 70 words each.(ix) Question numbers 26 to 41 in Section-B are multiple choice questions based on practical

skills. Each question is a one mark question. You are to select one most appropriate

response out of the four provided to you.

(i)

(ii)

(iii)

(iv)

(v) 1 4

(vi) 5 13 30

(vii) 14 22 50

(viii) 23 25 70

(ix) 26 41

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10. A person can see distant sign boards clearly but cannot read clearly a book which is at 25 cmfrom his eye. Identify the defect. Draw a labelled ray diagram to illustrate how this defect canbe corrected.

25 cm

11. A person needs a lens of power 2.5 dioptres for correcting his vision. Name the defect ofvision he is suffering from. Which lens will he be using for the correction ? Also find the focallength of the lens.

2.5 D

12. What are fossil fuels ? Why are they so called ?

13. Mention the steps taken by West Bengal Government to protect badly degraded sal forests.

14. Name the main product formed in the following reactions and write chemical equation for eachreaction.(a) C

2H

5OH+Na

(b) CH3CH

2OH 2 4

Conc. H SO443K

(c) CH2 CH

2+ Br

2

(a) C2H

5OH+Na

(b) CH3CH

2OH

2 4H SO

443K

(c) CH2 CH

2+ Br

2

15. The periodic Table given below consists of elements with atomic numbers from 3 to 18. Someof the elements are shown by letters but the letters are not the usual symbols of the elements.

Atomic Number 3 4 5 6 7 8 9 10

Element A B C

Atomic Number 11 12 13 14 15 16 17 18Element D E F G

(i) Write the electronic configuration of two elements which have similar chemicalproperties.

(ii) Which of these is a (a) metalloid, (b) noble gas ?(iii) Out of A and C, which one has greater atomic radius ? Give reason.

3 18

3 4 5 6 7 8 9 10

A B C

11 12 13 14 15 16 17 18

D E F G

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(i)

(ii) (a) (b)

(iii) A C

16. (a) Regeneration is not reproduction. Justify this statement with reason.(b) Suggest any two advantages of reproduction by Vegetative propagation of a plant.

(a)

(b)

17. (a) Name the scientist who worked out the rules of inheritance(b) Mention any two strategies that are used by different species for determining sex of

their new borns.

(a)

(b)

18. (a) Differentiate between dominant and recessive traits.(b) Genes control traits. Explain this statement with an example.

(a)

(b) (traits)

19. (a) Explain the difference between analogous and homologous organs.(b) Identify the analogous and homologous amongst the following :

Wings of an insect, wings of a bat, forelimbs of a frog, forelimbs of a lizard.

(a)

(b)

, ,

20. (a) State the laws of refraction.(b) The refractive indices of ruby and carbon disulphide with respect to air are 1.71 and 1.63

respectively. Find the refractive index of carbon disulphide with respect to ruby.

(a)

(b) 1.71 1.63

21. (a) Which mirror do we use as side view mirror in vehicles and why ?(b) A ray passing through the centre of curvature of a spherical mirror after reflection,

returns along the same path. Why ?

(a)

(b)

22. Describe the formation of rainbow in the sky with the help of a labelled diagram.

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23. (a) Identify the compounds A and B in the following reactions :

(i) C2H

5OH + CH

3CH

2COOH 2 4

Conc. H SO A + H

2O

(ii) CH3COOC

2H

5+ NaOH B + C

2H

5OH

Write the term used for the reactions (i) and (ii) above.(b) Draw the structure of the following compounds.

(i) Bromopentane (ii) Butanol(a) A B

(i) C2H

5OH + CH

3CH

2COOH

H SO2 4 A + H

2O

(ii) CH3COOC

2H

5+ NaOH B + C

2H

5OH

(i) (ii)

(b)

(i) (ii)

OR/

(a) Define the term homologous series of organic compounds ? Give an example.

(b) What would be observed on adding 5% solution of alkaline potassium permanganatedrop by drop to some warm ethanol taken in a test tube ? Write the name of thecompound formed during chemical reaction. Write a chemical test to identify thiscompound.

(a)

(b) 5%

24. (a) Give reasons :-(i) Placenta is extremely essential for foetal development.(ii) Blocking of vas deferens prevents pregnancy.(iii) Copying of DNA is important in the process of reproduction.

(b) With the help of suitable diagrams explain how reproduction occurs in Planaria. Alsoname the process involved.

(a)

(i)

(ii)

(iii) DNA

(b)OR/

(a) Give reasons :-(i) Blocking of Fallopian tubes prevents pregnancy.(ii) Testes are located outside abdominal cavity.(iii) Pre-natal sex determination has been banned by law.

(b) With the help of suitable diagrams explain how reproduction occurs in Hydra. Alsoname process involved.

(a)

(i)

(ii)(iii)

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28. Ethanoic acid

(a) is completely soluble in water.

(b) is insoluble in water.

(c) is partially soluble in water.

(d) forms turbid solution with water.

(a)

(b)

(c)

(d)

29. When acetic acid and sodium carbonate are made to react, it is observed that a gas is liberated

which turns lime water milky. The gas which is liberated is

(a) SO2 (b) H2 (c) NO2 (d) CO2

(a) SO2 (b) H2 (c) NO2 (d) CO2

30. Odour of acetic acid is like :

(a) scent (b) vinegar (c) apple (d) orange

(a) (b) (c) (d)

31. While determining the focal length of a convex lens, four students obtained the image of a

distant tree on the screen and represented the position and nature of the image formed as

shown in the following diagram.

The diagram correctly showing the image of the tree on the screen is :

(a) A (b) B (c) C (d) D

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(a) A (b) B (c) C (d) D

32. After focussing the image of a distant object on the screen four students, Puneeta, Sachin,Rubina and Anwar measured the distance between the screen and the concave mirror as shownin the following diagram. The student who will get the correct value of focal length is :

(a) Puneeta (b) Sachin (c) Rubina (d) Anwar

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(a) (b) (c) (d)

33. Which of the following sets represents the minimum material required for determining the

focal length of a concave mirror by obtaining the image of a distant object on a

screen ?

(i) Set A A candle, a concave mirror, mirror holder, a screen with stand,

measuring scale.

(ii) Set B A concave mirror, a burning candle, a screen with stand, a mirror holder,

measuring scale.

(iii) Set C A mirror holder, a concave mirror, a convex mirror, a measuring scale.(iv) Set D A concave mirror, a mirror holder, a screen with stand, a measuring

scale.

(a) Set A (b) Set B (c) Set C (d) Set D

(i) A

(ii) B

(iii) C

(iv) D

(a) A (b) B (c) C (d) D

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34. A student suggested the following guidelines to his friend for doing the experiment on tracing

the path of a ray of light passing through a rectangular glass slab for three different angles of

incidence :

(A) Draw the outline of the glass slab at three positions on the drawing sheet.

(B) Draw normals on the top side of these outlines near their left end.

(C) Draw the incident rays on the three outlines in directions making angles of 30, 45, 60

with the normals drawn.

(D) Fix two pins vertically on each of these incident rays at two points nearly 1 cm apart.

(E) Look for the images of the heads of these pins while fixing two pins from the other side,

to get the refracted rays.

When he showed these guidelines to his teacher, the teacher suggested corrections in three

guidelines labelled as :

(a) B, C, E (b) B, D, E (c) B, C, D (d) C, D, E

(A)

(B)

(C) 30, 45, 60

(D) 1 cm

(E)

(a) B, C, E (b) B, D, E (c) B, C, D (d) C, D, E

35. A student performs the experiment on tracing the path of a ray of light passing through a

rectangular glass slab for different angles of incidence. He measures the angles of incidence i,

angle of refraction r and angle of emergence e for all his observations. He would find that

in all cases.

(a) i is more than r but (nearly) equal to e

(b) i is less than r but (nearly) equal to e

(c) i is more than e but (nearly) equal to r(d) i is less than e but (nearly) equal to r

i, r e

(a) i r e

(b) i r e

(c) i e r

(d) i e r

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36. Which stage out of those marked I, II, III and IV is showing binary fission in Amoeba ?

(a) I (b) II (c) III (d) IV

I, II, III IV,

(a) I (b) II (c) III (d) IV

37. A student is given a permanent slide showing binary fission in Amoeba. The following are thesteps in focusing the object under the microscope, which are not in proper sequence-(i) Place the slide on the stage; look through the eyepiece and adjust the mirror

and diaphragm to get even illumination.(ii) Look through the eyepiece and raise the objective using coarse adjustment until

the object is focused.

(iii) Make the focus sharp with the help of fine adjustment.(iv) Look through the eyepiece and move the slide until the object is visible.The proper sequence of steps is :

(a) (i), (iii), (iv), (ii) (b) (ii), (iii), (iv), (i)(c) (iv), (iii), (ii), (i) (d) (i) (iv), (ii), (iii)

(i)

(ii)

(iii)

(iv)

(a) (i), (iii), (iv), (ii) (b) (ii), (iii), (iv), (i)(c) (iv), (iii), (ii), (i) (d) (i) (iv), (ii), (iii)

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38. The following are the sketches made by some students.

The sketch not illustrative of budding in yeast is :

(a) A (b) B (c) C (d) D

(a) A (b) B (c) C (d) D

39. In budding(a) cell divides transversely(b) cell divides longitudinally(c) nucleus divides followed by the development of protuberance(d) a small protuberance develops followed by nuclear division.

(a)

(b)

(c)

(d)

40. While performing an experiment with raisins, a student recorded the following data :Mass of water taken in a beaker 50 gMass of raisins before soaking 20 gMass of raisins after soaking 30 gMass of water left after experiment 40 g

The percentage of water absorbed by raisins is :(a)

50 40 g100

50 g

(b)

50 40 g100

40 g

(c) 30 20 g

10030 g

(d)

30 20 g100

20 g

50 g

20 g

30 g

40 g

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(a) 50 40 g

10050 g

(b)

50 40 g100

40 g

(c) 30 20 g

10030 g

(d)

30 20 g100

20 g

41. In order to remove extra water left on the surface of soaked raisins which one would youprefer to wipe off the raisins ?(a) dry cotton cloth (b) dry cotton wool(c) filter paper (d) dry nylon cloth

(a) (b)

(c) (d)

- o O o -