Question

Light travels from crown glass (n=1.52) into water (n=1.33). The angle incidence in
crown glass is 40o
. What is the angle of refraction in water

Answer 1

Given that,

Refractive index of crown glass = 1.52

Refractive index of water = 1.33

Angle of incidence = 40°

We need to calculate the angle of refraction in water

Using formula of Snell's law

$n_{1}\sin\theta_{i}=n_{2}\sin\theta_{r}$

$\dfrac{n_{1}}{n_{2}}=\dfrac{\sin\theta_{r}}{\sin\theta_{i}}$

Where, $n_{1}$ = Refractive index of crown glass

$n_{2}$ = Refractive index of water

$\theta_{i}$ = incident angle

Put the value into the formula

$\dfrac{1.52}{1.33}=\dfrac{\sin\theta_{r}}{\sin40}$

$\sin\theta_{r}=\sin40\times\dfrac{1.52}{1.33}$

$\sin\theta_{r}=0.715$

$\theta_{r}=\sin^{-1}(0.715)$

$\theta=45.6^{\circ}$

Hence, The angle of refraction in water is 45.6°