Question

Figures (a) and (b) show the refraction of a ray in air incident at ${60}^o$ with the normal to a glass-air and water-air interface, respectively. Predict the angle of refraction in a glass when the angle of incidence in water is ${45}^o$ with the normal to a water-glass interface [Fig.(c)].

Answer 1

Refractive index of glass ${\mu }_g=sin{60}^o/sin{35}^o=1.51$

For water ${\mu }_w=sin{60}^o/sin{47}^o=1.184$

So, refractive index of glass wrt to water can be ${\mu }_r={\mu }_g/{\mu }_w=1.275$

now,

${\mu }_r=sin{45}^o/sinr=1.275\Rightarrow r={36.68}^o\approx {37}^o$