Question

A driver at a depth 12 m inside water (μ = 4/3) see the sky in a cone of semi-vertical angle is

(a) sin^-1(\(\frac{4}{3}\))

(b) tan^-1 (\(\frac{4}{3}\))

(c) sin^-1 (\(\frac{3}{4}\))

(d) 90°

Answer 1

(c) sin^-1 (\(\frac{3}{4}\))

Required semi vertical angle = Critical angle i_c = sin^-1

\(\frac{1}{μ}\)= sin^-1(\(\frac{3}{4}\))