A man looks down on a fish of length 20 cm. His eye is 2m above the surface of the water `(mu = 4//3)` and the fish is 2m below the surface as shown in the figure the ratio of angular width `Delta theta` of the fish as seen by the man in presence of water to the `Delta theta` in the absence of water is `(Delta theta` is small)

Options

A. `6/5`
B. `5//6`
C. `7//8`
D. `8//7`

Answer

D

Explanation

`theta = (Arc)/("radius")`
`(Delta theta_(w))/(Delta theta_(a)) = (r_(a))/(r_(w)) = (2+2)/(2+(2)/(4//3)) = (4)/((7)/(2)) = (8)/(7)`