An insect at point 'P' sees its two images in the water mirror system as shown in the figure. One image is formed due to direct partical reflection from water surface and the other image is formed due to refraction, reflection & again refraction by water mirror system in order. Find the separation (in cm) between the two images. Mirror M has focal length 60 cm `[Take mu_(w)=4//3]`

Answer

`24 cm`

Explanation

Due to reflection at plane water surface
and other image formation is shown in the figure.
Due to refraction at water
`d_(1)=(12)/(1/(4//3))=16 cm`. For `M_(1),P_(1)` is an object.
for this `(1)/(v)+(1)/(-40)=(1)/(+60)rArrv=24 cm` this is at
It will act as object for water surface which makes image at `P".d_(2)=(24+24)/(4//3)=36 cm`
final images are `P'` and `P"`
distance `P'P"=36-12=24 cm.`