CBSE Science Practice Paper : Set III
1. Relate refractive index with the speed of light in the medium, 1
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2. Name the elements other than carbon that constitute carbohydrates. 1
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3. What is Faraday’s constant ? 1
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4. What are the units of rate of reaction. 1
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5. Give IUPAC name of H-C-H 1
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6. What are solar concentrators ? Give the usual shape of such concentrators. 2
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7. If an object is at 10 cm from a convex lens of focal length 15 cm, find (i) position {ii) nature of image formed. 2
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8. Name two places of one country where fields of natural gas are found. Why is it called a clean fuel ? Give two reasons. 2
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9. When two lenses of focal length 20 cm and - 30 cm are placed in contact. Find the equivalent. (i) Focal length (ii) Power 2
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10. Calculate the pH of the solution when hydrogen ion concentration is lxl0 -7 M. State whether the solution is acidic, basic or neutral.
The pH of solution is 4. Calculate hydrogen ion concentration. State the solution is acidic, basic or neutral. 2
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11. A 60 W, 220 V bulb and a 40 W, 220 V bulb are used with a supply of 220 V in series. Find the (*) Net power consumed (it) Identify the brighter of the two bulbs.
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A 60 W, 220 V bulb and a 25 W, 220 V bulb are to be connected to a 220 V supply. How will you connect them to get (/) maximum potential in each, («) current through each bulb. 3
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12. Write chemical equations to show what happens when ;
(i) Concentrated HNO3 is poured over sulphur powder. {ii) Na2CO3.10H2O crystals are exposed to air {Hi) Manganese dioxide is heated with aluminium. 3
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13. Draw a labelled diagram of an A. C. generator. Write the basic principle underlining its functioning.3
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14. How does pyrcx glass differ from soda glass ? Give composition of lead crystal glass. 3
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15. Explain the role of ciliary muscles, cornea and aqueous humour in helping the eye in its ability of accommodation. 3
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