Calculate the critical angle foe total internal reflection of light travelling from
(i) water into air
(ii) glass into water. Given, `.^(a)mu_(w) = 1.33` and `.^(a)mu_(g) = 1.5`.

Explanation

(i) When light travels from water to
air `.^(a)mu_(w) = (1)/(sin C)`
`sin C = (1)/(.^(a)mu_(w)) = (1)/(1.33) = 0.7518`
`:. C = sin^(-1) (0.7518) = 48^(@) 44'`
(ii) When light travels from glass into water
`.^(w) mu_(g) = (1)/(sin C'), i.e., (.^(a)mu_(g))/(.^(a)mu_(w)) = (1)/(sin C')`
or `(1.5)/(1.33) = (1)/(sin C')`
or `sin C' = (1.33)/(1.5) = 0.8866`
`:. C' = sin^(-1) (0.8866) = 62^(@) 27'`.