Physics - Geometrical Optics Question with Solution | TestHub

Inverted image from a concave mirror means a real image with m = -2:$m=-\frac{v}{u}=-2\Rightarrow |v|=2|u|$

Distance between object and image:$d=|v|-|u|=2|u|-|u|=|u|=12\text{cm}$

$u=-12\text{cm},v=-24\text{cm}$

$\frac{1}{f}=\frac{1}{v}+\frac{1}{u}=-\frac{1}{24}-\frac{1}{12}=-\frac{3}{24}\Rightarrow f=-8\text{cm}$

Absolute focal length: 8 cm