» CBSE Science Practice Paper : Set VIII : CBSE Sample Question Papers

16. What are the factors affecting the heat produced in a wire ? Define electric power. Relate electrical unit of electricity to joule. 3
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17. How are esters formed ? Write chemical equation for one such reaction. Write one use of esters. 3
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18. What are satellites ? Mention the types of orbits used to place them. How are they launched ? Explain,5
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19. With a labelled ray diagram explain how an Astronomical telescope works. Also give its magnification. 5
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20. Name the- chief ore of iron. How will you extract iron from this ore ? Write all the reactions involved in blast furnace and draw its neat and labelled diagram. How Ls iron refined ?

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Name chief ore of aluminium. How can we extract it from this ore ? Give two alloys of aluminium, their composition and uses. 5
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Section - B

21. What is meant by photochemical reaction ? 1
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22. Give one example each of binary fission and multiple fission. 1
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23. Define the terms: (a) nerve impulse, (b) axon. 1
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24. Explain the terms : (a) acid rain (b) ozone depletion. 2
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25. What are the two kinds of xylem elements ? 2
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26. How does heterotrophic organisms depend upon autotrophic organisms ? 3
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27. What is vegetative propagation ? Classify giving suitable examples. 3
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28. Who is the ‘founder of genetics1 ? How has the term ‘factor’ been modified today ? What was Mendel’s working material ? Briefly summarise his work. 3
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29. Mention the three main characteristic features of potable water. 3
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30. Write briefly about stages in photosynthesis process;

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Explain with a diagrammatic representation the mechanism of gaseous exchange between tissues and
blood. 5
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