Class 10 · Science · Science

9. Light - Reflection and Refraction

Try question 1

The mirror used as a rear-view mirror in vehicles is

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Answer and explanation

Answer: B. convex

A convex mirror gives an erect, smaller image and a wider field of view.

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Try question 2

The focal length of a spherical mirror of radius of curvature 20 cm is

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Answer and explanation

Answer: C. 10 cm

f = R/2 = 20/2 = 10 cm.

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Try question 3

The power of a lens of focal length +0.5 m is

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Answer and explanation

Answer: A. +2 D

P = 1/f (in metres) = 1/0.5 = +2 dioptre (a converging lens).

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