A fish is vertically below a flying bird moving vertically down toward water surface. The bird will appear to the fish to be

Options

A. moving faster than its speed and also from thereal distance
B. moving faster than its real speed and nearer than its real distance
C. moving slower than its real speed and also nearer than its real distance
D. moving slower than its real speed and away from the real distance

Answer

a.

Explanation

`(mu_(1))/(-u)+(mu_(2))/(v)=(mu_(2)-mu_(1))/(R)`
For a plane surface, `R=oo`
`:. (mu_(1))/(-u)+(mu_(2))/(upsilon)=0`
or ` (mu_(2))/(upsilon)+(mu_(1))/(u)` or `(mu)/(upsilon)-(1)/(u)`
or ` upsilon=mu_(2)u`
Clearly, to the fish, the bird appears farther than its distance.
Again, `(dupsilon)/(dt)=mu(du)/(dt)`
or Apparent speed of bird
`=` Refractive index `xx` Actual speed of bird .