Question

Consider the situation shown in the figure below. Water $({\mu }_w=\frac{4}{3})$ is filled in a beaker up to a height of $10cm$. A plane mirror is fixed at a height of $5cm$ from the surface of the water. The distance of the image of an object O kept at the bottom of the beaker, from the mirror will be:

• A. $15cm$
• B. $12.5cm$
• C. $7.5cm$
• D. $10cm$

Answer 1

The correct option is B

$12.5cm$

From the figure, it is clear that object appears to be raised by $\frac{10}{4}cm\left(2.5cm\right)$.
Hence, the distance between mirror and $O^{\prime }=5+7.5=12.5cm$.
So, the final image will be formed $12.5cm$ behind the plane mirror.