Question

A point object is placed at a distance of $62cm$ from a concave mirror of focal length $20cm$. A slab of the thickness $6cm$ and refractive index $\mu =3/2$ is placed in between the object and the mirror at a distance $1.5cm$ from the mirror. The distance (in $cm$ ) of the final image from the mirror is

Answer 1

Answer: 32

Shift, $x=t\left(1-\frac{1}{\mu }\right)=6\left(1-\frac{1}{\frac{3}{2}}\right)=2cm$
$\Rightarrow u$ for mirror $=62-2=60cm$
Now,
$\frac{1}{v}-\frac{1}{60}=-\frac{1}{20}$
$v=-30cm$
The final image will be formed at $32cm(30+2)$.