Physics - Geometrical Optics Question with Solution | TestHub

If$AB$is the position of the face of man then$A\text{'}B\text{'}$is the position of the image of a face. As the image is formed at$25 \mathrm{cm}$from the object.$\therefore$From concave mirror image is 15cm behind the mirror. So,$u=-10 cm, v= +15 cm$
$\Rightarrow \frac{1}{f}=\frac{1}{u}+\frac{1}{v}$$\Rightarrow \frac{1}{f}=\frac{1}{-10}+\frac{1}{15}=\frac{-3+2}{30}$
$\Rightarrow f=-30 \mathrm{cm}$. So, the radius of curvature,$=60 \mathrm{cm}$