The following figure represents a wave front AB which passes form air to another transparent medium and produces a new wave front CD after refraction . The refrective index of the medium is (PQ is the boundary between air and the medium).

Options

A. `(cos theta_(1))/(cos theta_(4))`
B. `(cos theta_(4))/(cos theta_(1))`
C. `( sin theta_(1))/(sin theta_(4))`
D. `(sin theta_(2))/(sin theta(3))`

Answer

C

Explanation

By snell's law :
`(sin i)/(sin r) = (mu_(2))/(mu_(1))`

for ` i= theta_(1) , r = theta_(4) and mu_(1) = 1`
`I = theta_(1) , r = theta_(4) " " mu_(1) = 1`
` mu_(2) = (sin theta_(1))/(sin theta_(4))`