Question

An object is placed in front of a convex mirror of focal length 30 cm is image formed is the half size of the image object then the position of the image from the mirror is

Answer 1

Given :

Focal length = -30 cm

v/u = (-1/2)

To find :

The distance of image from object

Solution :

• v/u = (-1/2)

      u = -2v

• In case of convex mirror

      (1/v) + (1/u) = (1/f)

• By substituting the values

       (1/v) + (1/-2v) = -(1/30)

       1/2v = -1/30

       v = -15 cm

The distance of image from object is  -15 cm

Answer 2

Explanation:

Since, mirror is convex

f=30cm

And m=-v/u=-1/2

u=2v

1/v+1/u=1/f

1/v=1/f-1/u

Put the value and we get +ve 15