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What is the nature of the mirror having a focal length of -20 cm?

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Question

What is the nature of the mirror having a focal length of -20 cm?
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Solution

The mirror having -20 cm as its focal length is a concave mirror because the focal length is taken negatively only in case of a concave mirror.
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Chapter 6: Light - Spherical Mirrors [Page 258]

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Frank Physics [English] Class 9 ICSE
Chapter 6 Light
Spherical Mirrors | Q 22 | Page 258

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