Question

A meter scale is placed along the axis of convex mirror of focal length 25 cm , it’s nearer end being at a distance of 50 cm. Calculate the size of image formed.

Answer 1

The mirror formula :

1/f = 1/u + 1/v

u = image distance

v = object distance

f = focal length

Now :

v = 50 cm

f = 25 cm

1/25 = 1/50 + 1/u

1/u = 1/25 - 1/50

1/u = 1/50

u = 50 cm

Magnification :

Image distance / object distance

50/50 = 1

Size of image :

1 meter × 1 = 1 meter

= 1 meter

Answer 2

Explanation: From diagram we can do it very quickly and easily