Answer
(a) $3.0cm$
(b) $-0.49$
(c) increase
Work Step by Step
(a) We know that
$\frac{1}{f}=\frac{1}{d_{\circ}}+\frac{1}{d_i}$
We plug in the known values to obtain:
$\frac{1}{f}=\frac{1}{4.5}+\frac{1}{2.2}$
This simplifies to:
$f=1.477cm$
As $R=2f$
$\implies R=2(1.477)=3.0cm$
(b) The magnification of the image can be determined as:
$m=-\frac{d_i}{d_{\circ}}$
We plug in the known values to obtain:
$m=-\frac{-2.2cm}{4.5}=-0.49$
(c) We know that if the object is moved closer to the mirror, the magnification of the image increases.
