Question

an object of height 2 cm is placed at a distance of20 cm in front of a concave mirror of focal length 12 cm . find the position , size and nature of the image.

Answer 1

given ,

focal length (f ) = - 12 cm

object distance ( u ) = -20 cm

use formula ,

1/u + 1/ v = 1/ f

1/(-20) + 1/v = 1/(-12)

1/v = 1/20 - 1/12

=-8/20 x 12 = - 1/30

v = - 30 cm

hence image form 30 cm distance from the pole of mirror from left side .

m = -v/u = height of image / height of object

-(-30)/(-20) = height of image /2 cm

height of image = -3 cm

hence image form left side from the pole below the x -axis and image is real inverted and larger then object .

Answer 2

I hope this helps you