Question

The distance between a real object and it's real image is 56cm formed by converging lens focal length of lens is

Answer 1

Answer:

If the object is at a distance equal to twice the focal length of the lens then the image is also at a distance equal to twice the focal length.

Let,

S= object distance

S'= Image distance

f. = focal length

1/f = 1/S + 1/S'

S = 2f = S'

So,

1/f = 1/2f × 1/2f = 1/f

This is the minimum distance between object and image