Q1 of 117 Page 10

Define the principal focus of a concave mirror.

All the light rays which are travelling parallel to the principal axis are bound to meet at a point on the principal axis after reflection from the mirror. This point on the principal axis is called the principal focus of the mirror.

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86 Give the applications of plane mirror. 87 Give the expression for refractive index in terms of speed of light. 2

The magnification produced by a plane minor is +L What does this mean ?

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Find the power of a concave lens of focal length 2 m.