Question

Size of the image of an object by a concave lens pf focal length 20 cm is observed to be reduced to 1/3rd of the size .Find the distance of the object from the lens​

Answer 1

h'/h = v/u

1/3h/h =v/u

v = u/3

from lens formula

1/v - 1/u = 1/f

1/u/3 - 1/u = 1/f

3/u - 1/u = 1/-20

u = -40 cm..

HOPE THIS HELPED

Answer 2

Answer:

Explanation:

Given:

F=-20

M=-1/3