A,B and C are the parallel sided transparent media of refractive index `n_(1),n_(2)` and `n_(3)` respectively.
The are arranged as shown in the figure. A ray is incident at an angle `theta` on the surface of separation of A and B which is as shown in the figure. After the refraction into the medium B, the ray grazes the surface of separation of the media B and C. Then, `sintheta`=

Options

A. `(n_(3))/(n_(1))`
B. `(n_(1))/(n_(3))`
C. `(n_(2))/(n_(3))`
D. `(n_(1))/(n_(2))`

Answer

A

Explanation

Applying Snell.s law at M,
`n_(1)sintheta=n_(2)sintheta.` . . .(i)
Again, applying Snell.s law at N
`n_(2)sintheta.=n_(3)sin90^(@)`
`n_(2)sintheta.=n_(3)sin90^(@)` `n_(1)sintheta=n_(3)` (Using (i))
`sintheta(n_(3))/(n_(1))`