SUMMATIVE ASSESSMENT - II

'(id5feid l:Rtarr - II

SCIENCE

Rl$1i.=t

Maximum Marks: 80

3ll�37cli: 80

Time allowed : 3 hours

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CBSE QUESTION PAPERCLASS-X

General Instructions :

(i) The question paper comprises of two sections, A and B. You are toattempt both the sections.

(ii) All questions are compulsory.(iii) There is no overall choice. However, internal choice has been

provided in all the three questions of five marks category. Only oneoption 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) Questions number 1 to 4 in Section A are one mark questions.These are to be answered in one word or one sentence.

(vi) Questions number 5 to 13 in Section A are two mark questions.These are to be answered in about 30 words each.

(vii) Questions number 14 to 22 in Section A are three mark questions.These are to be answered in about 50 words each.

(viii) Questions number 23 to 25 in Section A are five mark questions.These are to be answered in about 70 words each.

(ix) Questions number 26 to 41 in Section B are multiple choicequestions based on practical skills. Each question is a one markquestion. You are to select one most appropriate response out of thefour provided to you.

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SECTION A

�at

1. Draw the structure for ethanoic acid molecule, CH3COOH. 1

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2. Give an example of a phenomenon where Tyndall effect can beobserved. 1

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3. What is meant by biological magnification ? 1

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4. Give an example to illustrate that indiscriminate use of pesticides mayresult in the degradation of the environment. 1

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5. How does the valency of elements vary (i) in going down a group, and(ii) in going from left to right in a period of the periodic table ? 2

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(ii) fcnm � # � 'B Gn:t � # ?

6. In the modern periodic table, the_ element Calcium (atomic number=20) is surrounded by elements with atomic numbers 12, 19, 21 and 38.Which of these elements has physical and chemical propertiesresembling those of Calcium and why ? 2

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7. State any four characteristics of the image of an object formed by aplane mirror. 2

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8. Draw a ray diagram to show the refraction of light through a glassprism. Mark on it (a) the incident ray, (b) the emergent ray and (c) theangle of deviation. 2

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9. Explsiin with the help of a diagram, how we are able to observe thesunrise about two minutes before the sun gets above the horizon.

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10. List any four reasons for vegetative propagation being practised in thegrowth of some type of plants.

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11. Describe the role of fallopian tubes in the female reproductive system.

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12. List any four disadvantages of using fossil fuels for the production ofenergy.

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13. Give two examples each of the following :

(i) Renewable sources of energy

(ii) Non-renewable sources of energy

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14. Write chemical equations for what happens when

(i) sodium metal is added to ethanoic acid.

(ii) solid sodium carbonate is added to ethanoic acid.

(iii) ethanoic acid reacts with a dilute solution of sodium hydroxide.

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15. The atomic number of an element is 16. Predict(i) the number of valence electrons in its atom(ii) its valency(iii) its group number(iv) whether it is a metal or a non-metal(v) the nature of oxide formed by it(vi) the formula of its chloride 3

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16. An . object is placed between infinity and the pole of a convex mirror.Draw a ray diagram and also state the position, the relative size and. the nature. of the image formed. 3

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17. What· is the principle of reversibility of light ? Show that the incidentray of light is parallel to the emergent ray of light vyhen light fallsobliquely on a side of a rectangular glass slab. 3

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18. What eye defect is myopia ? Describe with a neat diagram how thisdefect of vision can be corrected by using a suitable lens. 3

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19. What does HIV stand for ? Is AIDS an infectious disease ? List anyfour modes of spreading AIDS. 3

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20. Describe any three ways in which individuals with a particular traitmay increase in population. 3

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21. State the evidence we have for the origin of life from inanimate matter. 3

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22. What are fossils? What do they tell us about the process of evolution? 3

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23. (a) State two properties of carbon which lead to a very large numberof carbon compounds.

(b) Why does micelle formation take place when soap is added towater ? Why are micelles not formed when soap is added toethanol?

OR

Explain isomerism. State any four characteristics of isomers. Draw

5

the structures of possible isomers of butane, C4H10.5

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24. (a) What is meant by 'power of a lens' ?

(b) State and define the S.I. unit of power of a lens.

(c) A convex lens of focal length 25 cm and a concave lens of focallength 10 cm are placed in close contact with each other.Calculate the lens power of this combination. . 5

OR

(a) Draw a ray diagram to show the formation of image of an objectplaced between infinity and the optical centre of a concave lens.

(b) A concave lens of focal length 15 cm forms an image 10 cm fromthe lens.Calculate(i) the distance of the object from the lens(ii) the magnification for the image formed(iii) the nature of the image formed

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(ii) � Slfaf¾kl � � �(iii) � Sl@f¾kl ch1 �

5

25. With the help of suitable diagrams, explain the various steps ofbudding in Hydra. 5

OR

What is binary fission in organisms ? With the help of suitable diagrams, describe the mode of reproduction in Amoeba. 5

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SECTION B

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26. To find the focal length of a concave mirror, Sita should choose which

one of the following set-ups ? 1

(A) A mirror holder and a screen holder

(B) A screen holder and a scale

(C) A mirror holder, a screen holder and a scale

(D) A screen, a mirror, holders for them and a scale

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CD) � w, � _;tfur, � � ITT 3m: � �

27. By using a convex lens, a student obtained a sharp image of his

class-room window grill on a screen. In which direction should he move

the lens to focus a distant tree instead of the grill ? 1

(A) Towards the screen

(B) Away from the screen

(C) Very far away from the screen

(D) Behind the screen

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28. To determine the focal length of a convex lens by obtaining a sharpimage of a distant object, the following steps were suggested which arenot in proper sequence

I. Hold the lens between the object and the screen.

II. Adjust the position of the lens to form a sharp image.

III. Select a suitable distant object.

IV . Measure the distance between the lens and the screen.

The correct sequence of steps to determine the focal length of the lens is 1

(A) III, I, II, IV

(C) III, IV , II, I

(B) III, I, IV, II

(D) I, Ii, III, IV

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(C) III, IV, II, I

(B) III, I, IV, II

(D) I, II, III, IV

29. In these diagrams, the angle of refraction r has been correctly markedin which diagram ? 1 ·

I II

(A) I (B) II

III

(C) III (D) IV

IV

I

(A) I

(C) III

II III

(B) II

(D) IV

30. For a ray of light passing through a glass slab

the lateral displacement was correctly measured as

(A) AB (B) PQ

(C) CD (D) PR

IV

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(A) AB

(C) CD

(B) PQ

(D) PR

1

31. Iron nails were dipped in an aqueous solution of copper sulphate. Afterabout 30 minutes, it . was observed that the colour of the solutionchanged from 1

(A) colourless to light green.

(B) blue to light green.

(C) blue to colourless.

(D) green to blue.

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32. A cleaned aluminium foil was placed in an aqueous solution of zincsulphate. When the aluminium foil was taken out of the zinc sulphatesolution after 15 minutes, its surface was found to be coated with asilvery grey deposit. From the above observation it can be concludedili� 1

(A) aluminium is more reactive than zinc.

(B) zinc is more reactive than aluminium.

(C) zinc and aluminium both are equally reactive.

(D) zinc and aluminium both are non-reactive.

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(D) 00 am QcjMRlf4 � � � I

33. Vapours of acetic acid smell

(A) pungent like vinegar.

(B) sweet like rose.

(C) suffocating like sulphur dioxide.

(D) odourless like water.

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(B) � � 1fuft I

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(D) ���I

34. Acetic acid reacts with solid sodium hydrogen carbonate

(A) slowly forming no gas.

(B) �igorously with effervescence.

(C) slowly without effervescence.

(D) vigorously without gas formation.

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(B) � � � 1q�1$2. � �

(C) tjft-tjft � 1�1�1$2. � I

(D) ����im�

1

1

35. A student added acetic acid to test tubes I, II, III and IV containingthe labelled substances and then brought a burning splinter near themouth of each test tube.

'I

NaOH

II

NaCl

III

NaHC03

IV

Ca(OH)2

The splinter would be extinguished when brought near the mouth of test tube 1 ·

(A) I

(B) II

(C) III

(D) IV

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I II III IV

NaOH NaCl NaHC03 Ca(OH)2

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(A) I

(B) II

(C) III

(D) IV

36. The shape of yeast cell is

(A) only spherical.

(B) only oval.

(C) irregular.

(D) both oval and spherical.

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(B) �� I

(C) �-� (61f.P-1fl-la) I

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37. The steps involved in observing a slide under a microscope are givenbelow. They are not in proper seque·nce.

I. Focus the object under high power of the microscope.

II. Place the slide on the stage of the microscope.

III. Arrange the mirror to reflect maximum light to the slide.

IV. Focus the object under low power of the microscope.

The proper sequence of steps is

(A) II, III, IV, I

(B) I, II, III, IV

(C) IV, III, II, I

(D) III, I, II, IV

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(A) II, III, Iv, I

(B) I, II, III, IV

(C) IV, III, II, I

(D) III, I, II, IV

1

1

38. The given figures illustrate binary fission in Amoeba in improperorder.

08 � (� ·�

I II III IV

The correct order is 1

(A) III, IV, II, I

(B) IV, III, II, I

(C) II, III, IV, I

(D) I, III, IV, II

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G)8�g� I II III IV

��� (A) III, IV, II, I

(B) IV, III, II, I

(C) II, III, IV, I

(D) I, III, IV, II

39. During the course of an experiment, 'to determine the percentage ofwater absorbed by raisins', raisins are weigh�d 1

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(B) � cl1l'Z � I

(C) m � "ITT � sqi: � � am I

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40. The colour of raisins as used in the experiment, 'to determine thepercentage of water absorbed by raisins' was 1

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(B) <Tim

(C) � �

(D) �

41. Following are the steps involved ·in the experiment 'to determine thepercentage of w�ter absorbed by raisins'. They are not in propersequence.I. Soak the raisins in fresh water. ·II. W eigp dry raisins.III. Weigh soaked raisins.rv. Wipe out soaked raisins.

The correct sequence of steps is (A) I, II, III, IV(B) II, I, IV, III(C) II, I, III, IV(D) I, II, IV, III

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ri cnr � sm �

(A) I, II, III, IV(B) II, I, IV, III(C) II, I, III, IV(D) I, II, IV, III

1

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