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Thursday, 31 December 2015

SUMMATIVE ASSESSMENT – I SCIENCE Class – X

                              SUMMATIVE ASSESSMENT – II
                                         SCIENCE
                                        Class – X
Time allowed : 3 hours                      M.M : 90
General 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. 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 3 in Section-A are one mark questions. These are to be answered in one word or in one sentence.
(vi) Question numbers 5 to 11 in Section-A are two marks questions. These are to be answered in about 30 words each.
(vii) Question numbers 12 to 23 in Section-A are three marks questions. These are to be answered in about 50 words each.
(viii) Question numbers 24 to 27 in Section-A are five marks questions. These are to be answered in about 70 words each.
(ix) Question numbers 28 to 43 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.
                               SECTION-A
1. Molecular formula of a hydrocarbon is C3H8. Draw its complete structure and write its name.

2. Mention the name of a structure found in human eye that controls size of pupil.

3. Consider a food chain of the following- fish, crab, plankton, shark Arrange the above chain in proper order of trophic level.

4. Mention the role of decomposers in our eco-system.

5. State Modern Periodic Law. Name the two elements of first period.

6. Arrange the following elements in the descending order of atomic size and give a reason for your answer. Mg, Cl, P, Ar (Atomic numbers of the above elements are 12, 17, 15, 18 respectively.

7. Differentiate between the fission of uni-cellular organism Leishmania and of Plasmodium.

8. Mention any four ways of asexual reproduction.

9. (a) State Snell’s Law of refraction.
(b) Define refractive index of a medium and express it mathematically.

10. (a) What is the least distance of distant vision for the normal eye?
(b) Does the above distance increase or decrease for long-sighted eye? Give reason for your answer with diagram.

11. (a) Why danger signals are red in colour?
(b) What would have been the colour of sky if the earth had no atmosphere? Give reason for your answer.
12. Fossil fuels are being increasingly used as source of energy. List any two reasons for replacing these by alternate sources of energy.

13. List any two reasons due to which construction of large dams is opposed.

14. (a) Write chemical name and formula of Vinegar?
(b) Describe with a chemical equations what happens when sodium reacts with ethanol.

15. (a) What are metalloids ?
(b) Name any four metalloids

16. (a) What are sexually transmitted diseases? Name any one which is caused by bacteria and one caused by viral infection.
(b) Mention any two methods to avoid such diseases.

17. Explain in brief the factors that can lead to the rise of new species.

18. Define the following terms for a lens with the help of diagram.
(a) Optical centre (b) Principal axis (c) Principal focus

19. What are homologous organs? How do they provide evidence in support of evolution?

20. Draw the image formation by a concave mirror of focal length 15cm for the following positions of object (diagrams may not be drawn to the scale) Indicate the nature and relative size of image
(i) object is placed at 30cm from mirror
(ii) object is placed at 10cm from mirror 15 cm(i) 30cm (ii) 10cm

21. (a) Explain the difference between a converging and diverging lens with the help of diagram.
(b) Power of a lens is - 1.5 D. What is the nature of this lens?

22. (a) Draw a diagram to show the formation of image of a distant object by a myopic eye. How can such an eye –defect be rectified ?
(b) State two reasons due to which this eye defect may be caused.

23. In human beings, the statistical probability of getting either a male or a female child is 50:50. Give reasons and explain with the help of diagram.

24. Write balanced chemical equation for the following –
(a) Methane is burned in sufficient air.
(b) Ethanol is treated with sodium.
(c) Ethanoic acid is reacted with sodium hydroxide.
(d) Ethanoic acid is treated with Sodium carbonate.
(e) Ethanol is mixed with Ethanoic acid in the presence of an acid.

25. (a) Draw a diagram illustrating germination in a flowering plant and label – Stigma, Pollen grain,
Male germ cell, Female germ cell.
(b) Describe the process of germination.
OR
(a) Draw a diagram showing longitudinal section of a flower and label – Stigma, Ovary, Anther, and Filament.
(b) How is the process of pollination different from fertilization.

26. (a) Illustrate with the help of ray diagram for a concave mirror the following terms –
(i) Principal focus (ii) Center of curvature
(b) The image of a candle flame formed by a lens is obtained on a screen placed on the other side of the lens. If the image is three times the size of the flame and the distance between lens and image is 80cm, at which distance should the candle be placed from the lens? What is the nature of the lens ? Also give the nature and position of image.
OR
(a) Illustrate with the help of ray diagram for a convex mirror the following terms –
(i) Principal focus (ii) Center of curvature.
(b) An object 2cm high when placed in front of a converging mirror produces a virtual image 3cm high. If the object is placed at a distance of 8 cm from the pole of the mirror, calculate :
(i) the position of the image
(ii) the focal length of the converging mirror.


27. Name any four modes of reproduction used by single organisms. With the help of a neat diagram
explain the process of regeneration in Planaria. “More complex organisms cannot give rise to new
individuals through regeneration”. Why ?
OR
Distinguish between pollination and fertilisation. Explain why, pollination may occur without
fertilization but fertilisation will not take place without pollination. Draw a neat diagram showing
the process of pollination and fertilisation in a flowering plant and label the following on it.
(i) Female germ cell (ii) Male germ cell (iii) Ovary (iv) Pollen tube






































2. Iris
3. Plankton, crab, fish, shark.


4. These micro organisms break down the complex organic substances into simple inorganic
substances that go into the soil and are used once more by plants.

5. Modern Periodic law states that “The chemical properties of the elements are the periodic functions of their atomic numbers.”
Hydrogen and Helium 6. Mg, P, Cl, Ar.
Increase in atomic no. means increase in nuclear charge which tends to pull the electrons closer to the nucleus and reduces size of atom.

7. Leishmania – binary fission occurs in definite orientation in relation to the whip like structure. Plasmodium – multiple fission.

8. Fission, Regeneration, budding, vegetative propagation, spore formation.

9. (a) Snell’s Law : - When a ray of light passes from one medium to another, it refracts and the
ratio of the Sin of the I to the Sin of r is always a constant for a pair of media.

10. (a) 25 cm
(b) Increases Rays coming from distant object are focused beyond retina. Only light coming from far point P are focused on retina.
This distance increases in Hypermetropia as we can see the far distant objects easily.

11. (a) Because red colour is least deviated
(b) Since there will be no particles to scatter light, sky will appear black.

12. These are :-
(1) Non renewable
(2) Causes pollution
(3) Contribute to global warming

13. (a) Ecosystem is disturbed
(b) Large areas get submerged causing social problems
(c) Economic problems

14. (a) 5-8% of acetic acid solution in water
(b) When sodium reacts with ethanol, then a sodium salt sod. Ethanoate is formed carbon-dioxide
gas is evolved along with water vapors. The involved rxn is as follows :
CH3COOH+NaHCO3 → CH3COONa + H2O + CO2

5. (a) Borderline elements which are intermediate in properties between metals and non-metals.
(b) Boron, silicon, germanium, arsenic, or any correct name.

16. (a) The diseases that are sexually transmitted .
(i) gonorrhoea or syphillis
(ii) warts, HIVAIDS.
(b) (i) use of condoms on penis.
(ii) use covering on vagina.

17 Geographical isolation leads to genetic drift and natural selection as the isolation in a particular
area leads to change in genes due to natural selection because only the best suited organisms
are able to survive.

18. (a) The centre of the lens (O)
(b) An imaginary straight line passing through the two centres of curvatures AB)
(c) parallel rays after refraction from a convex lens converge at focus. (F)

19. Organs having same basic structure but different functions e.g forelimbs of bird, man and frog. It
shows that the basic origin is same (common ancestor)

20. Real and equal in size to object virtual and enlarged

Read more topics ...
light-reflection-refraction-objectives
The-human-eye-and-colourful-world
Human-eye-and-colourful-world
Comparison-between-ac-and-dc
Electricity-test
Magnetic-effects-of-electric
Elecricity-notes
Magnetic-effects-of-electric-current

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