Question

Consider the situation shown in figure. Water `(mu=4//3)` is filled in a beaker upto a height of 10cm.
A plane mirror is fixed at a height of 5 cm from the surface of water. Distance of image from the mirror after reflection from it of an object O at the bottom of the beaker is

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

Answer 1

Correct Answer - b.
Distance of first image `(I_(1))` formed after refraction from the plane surface of water is
`(10)/(4//3)=7.5cm`
from water surface `(d_(app)=(d_(actual))/(mu))`.
Now, distance of this image is `5+7.5=12.5cm` from the plane mirror. Therefore, distance of second image `(I_(2))` will also be equal to 12.5 cm from the mirror.