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CBSE Class 10 Science Solved Question Paper 2011

Short Answer Type

31.

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

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32.

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

1201 Views

33.

What does HIV stand for? Is AIDS an infectious disease? List any four modes of spreading AIDS.

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34.

Describe any three ways in which individuals with a particular trait may increase in population.

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35.

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

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36.

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

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Long Answer Type

37.

a) State two properties of carbon which lead to a very large number of carbon compounds.
b) Why does micelle formation take place when soap is added to water? why are micelles not formed when soap is added to ethanol ?

Or

Explain isomerism. State any four characteristics of isomers. Draw the structure of possible isomers of butane C₄H₁₀.

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38.
a) What is meant by the '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 focal length 10 cm are placed in close contact with each other.
Calculate the lens power of this combination.

a) The ability of a lens to converge or diverge a beam of the light ray is known as the Power (P) of the lens.
Power is equal to the reciprocal of the focal length.

That is, P = $1 over straight f$
b) SI unit of the power of a lens is Dioptre.

1 diopter = $fraction numerator 1 over denominator left parenthesis 1 straight m right parenthesis end fraction$ = 1 m^-1
1 m is the focal length of the lens.

c) Given,

Focal length, f = +25 cm

= $plus open parentheses 25 over 100 close parentheses straight m$
$straight P subscript 1 space equals space 1 over straight f subscript 1 space space space space space equals space 100 over 25 rightwards double arrow space straight P subscript 1 space equals space plus 4 space straight D$

Focal length, f₂ = -10 cm = $negative open parentheses 10 over 100 close parentheses m$
Power, P₂ = $1 over straight f subscript 2 space equals space minus open parentheses 100 over 10 close parentheses m space equals space minus space 10 space D$
Power of the combination of lens, P = P₁ + P₂P = 4 D - 10 D = - 6 D