Question

an arrow is placed at a distance of 25 cm from a convex mirror of focal length 20 cm.Find the image distance with the method

Answer 1

Take f = 20 cm ; u = - 25 cm ;v =?

By formula of mirror,

I/v +1/u =1/f.

or, 1/v =1/f - 1/u

or, 1/v = 1/20 - 1/-25

or, 1/v =1/20 +1/25

or, 1/v = (4+5)/100

or, v =100/9 =11.11 cm

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