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A stationary observer O looking at a fis...

A stationary observer O looking at a fish F in water `(mu_(w)=4//3)` through a converging lens of focal length `90.0cm` . The lens is allowed to fall frelly from a height `62.0cm` with its axis vertical. The fish and the observer are on the principal axis of the lens. The fish moves up with constant velocity `100cm//s`. Initially it was at depth of `44.0cm` . Find the velocity (in cm//s) with which the fish appears to move with respect to lens to the observer at `t=0.2 s`. (take `g=10m//s^(2))`

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The correct Answer is:
2475 cm/s
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