Question

Where will the image form when we place an object, on the principal axis of a concave mirror at a point between focus and centre of curvature?

Answer 1

Let us keep an object at $\frac{3f}{2}$ i.e. between focus and center of curvature

Now $u=\frac{-3f}{2}$

$f=-f$

So from mirror formula

$\frac{1}{v}+\frac{1}{u}=\frac{1}{f}$

$\frac{1}{v}-\frac{2}{3f}=\frac{-1}{f}$

$\frac{1}{v}=\frac{-1}{3f}$

$v=-3fcm$

Hence image will form beyond center of curvature.