The magnification of the real images produced by a convex lens varies from one to infinity. What are the values of the distances of the object from the lens for these magnifications ?

Options

A. f and 0
B. `oo` and f
C. 2f and f
D. 2f and 3f

Answer

C

Explanation

When `u=f, v=oo` and the magnification
`=(I)/(o)=(v)/(u)=oo`
and when u=2f, v=2f and the magnification
`=(v)/(u)=(2f)/(2f)=1`
Thus The object should be placed at 2f and f.