Refractive indices of water an glass are `4//3 and 3//2` respectively. A ray of light travelling in water is incident on the water glass interface at `30^@`. Calculate the angle of refraction.

Options

A. `sin^(-1)((8)/(18))`
B. `sin^(-1)((4)/(3))`
C. `sin^(-1)((3)/(2))`
D. `sin^(-1)((18)/(8))`

Answer

A

Explanation

Here, `.^(a)mu_(w)=(4)/(3), .^(a)mu_(g)=(3)/(2),.^(w)mu_(g)=(.^(a)mu_(g))/(.^(a)mu_(w))=(9)/(8)`
Angle of incidence in water, i=`30^(@)`, r= ?
`(sini)/(sinr)=.^(w)mu_(g)=(9)/(8)`
`sinr=(8)/(9)sini=(8)/(9)sin30^(@)=(8)/(9)xx(1)/(2)=(8)/(18)` or `r=sin^(-1)((8)/(18))`