Question

The refractive index of water with respect to air is $1.33$. Calculate the critical angle for water air interface

• A. ${26}^{\circ }$
• B. ${22}^{\circ }{6}^1$
• C. ${48}^{\circ }{45}^1$
• D. ${76}^{\circ }{5}^1$

Answer 1

Answer: (C)

${48}^{\circ }{45}^1$

From snells law we have

${}^a{u}_w=\frac{1}{\sin i_c},$

$\sin i_c=\frac{1}{{}^a{u}_w}=\frac{1}{1\cdot 33}$

$i_c={48}^{\circ }{45}^1$.