(a) A concave mirror has radius of curvature 20 cm. Calculate the distance of an object from the mirror so as to form an image of magnification -2.…

(a) \(\displaystyle m=-\frac{\mathrm{v}}{u}\) \[-2=-\frac{\mathrm{v}}{u} \] \[\mathrm{v}=2 u \] \[\frac{1}{f}=\frac{1}{\mathrm{v}}+\frac{1}{u} \] \[\frac{1}{-10}=\frac{1}{2 u}+\frac{1}{u} \] \[u=-15 \mathrm{~cm} \] \[\mathrm{v}=-30 \mathrm{~cm} \]

(b) Yes, same image is formed with reduced intensity, because reflecting area get reduced and laws of reflection still hold good for remaining part of the mirror.