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.

Explanation

Here, `.^(a) mu_(w) = 4//3` and `.^(a)mu_(g) = 3//2`
Refraction index of glass w.r.t. water
`.^(w)mu_(g) = (.^(a)mu_(g))/(.^(a)mu_(w)) = (3//2)/(4//3) = (9)/(8)`
Now, in water, `i= 30^(@), r = ?`
`(sin i)/(sin r) = .^(w)mu_(g) = (9)/(8)`
`sin r = (8)/(9) sin i = (8)/(9) sin 30^(@) = (4)/(9) = 0.4444`
`r = sin^(-1) (0.4444) = 26^(@) 23'`.