Question
Mon November 12, 2012 By: Rishav Singh

How far should anobject be placed from the pole of a concave mirror of focal length 20 cm to form a real image of the size exactly 1/4th the size of the object

Expert Reply
Mon November 12, 2012
focal length of concave mirror, f =-20cm
The distance between the object and the mirror (u) = ?
The distance between the image and the mirror (v) = ?
Let the size of the object be equal to 1.
Given size of the image = 1/4 size of the object.

ho = 1



But we know that









(-3/u) = (-1/20)
u = 60cm
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