Question

A convex lens of focal length $f$ produces a real image $\frac{1}{n}times$ the size of the object. Find the position of the object. The distance of the object from the lens is

• A. $-\frac{f}{n}$
• B. $-nf$
• C. $-(n-1)f$
• D. $-(n+1)f$

Answer 1

The correct option is D $-(n+1)f$

As we know,

$m=\frac{f}{(f+u)}\Rightarrow -\frac{1}{n}=\frac{f}{(f+u)}\Rightarrow u=-(n+1)f$