Question

Minimum distance between and object and real image of a convex lense is *

Answer 1

Let the distance between the object and its real image formed by convex lens be d1. Let the distance of the object from lens be x,so,the image distance from the lens is (d-x).

Then, x=d±√d²-4fd/2

For real values of x,

d² ≥4fd

that is ,d≥4f

The minimum distance between an object and its real image in a convex lens is 4f.

hence, answer is 4f