Question

A fish lies at the bottom of 4 m deep water lake. A bird flies 6 m above the water surface. Then distance between (Fish and Bird on same vertical line) -

• A. bird and image of fish is 9 m
• B. fish and image of bird is 12 m
• C. fish and image of bird is 8 m
• D. fish and image of bird is 10 m

Answer 1

The correct option is A bird and image of fish is 9 m

${\mu }_w=\frac{4}{3}$

Real depth of fish $D=4m$

${\mu }_w=\frac{D}{d}$

$\Rightarrow \frac{4}{3}=\frac{4}{d}$

Hence apparent depth of fish $d=3m$

It is given that the bird is $6m$ above the water surface.

Hence the distance between the bird and the image of the fish $=6+3=9m$

Hence the correct answer is option (A).