A small fish 0.4 m below the surface of a lake is viewed through a simple converging lens of focal length 3 m.the lens is kep at 0.2 m above the water surface such that the fish lies on the optical axis of the lens. Find the image of the fish seen by the observed. `(mu_(water)=(4)/(3))`

Explanation

Shift by water `=40(1-(1)/((4)/(3)))=10cm`
Image by lens:
`u=-(20+30)=-50cm,f=300cm,v=?`
`(1)/(v)-(1)/(u)=(1)/(f)`
`(1)/(v)-(1)/(-50)=(1)/(300)implies(1)/(v)=(1)/(300)-(1)/(50)=(1-6)/(300)`
`v=-60cm`
Image of fish is formed on the same side of fish and at a distance 60 cm from lens. Image of fish if formed at fish itself.