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

(I) Image by partial reflection = 12 cm below water surface
(II) For mirror object appears at
`u/(4//3)=24/(4//3)+12/1`
`u=24+12xx4/3 Rightarrow u=40` cm
Reflection `1/v+1/(-40)=1/(+60) Rightarrow 1/v=1/60+1/40 Rightarrow v=+24` cm
Reflection `(Al)/I=48/(4//3)=36` cm
Thus, distance between two images `=36-12=24` cm