Question

1. Light is incident on a clear-plastic block at an angle of 45°. The speed of light in the plastic is tz, where is
the speed of light in vacuum Find the angle of refraction.​

Answer 1

$\large\underline{\underline{\sf Given:}}$

• Angle of incident $\sf{(sini)}$= 45°

$\large\underline{\underline{\sf To\:Find:}}$

• Angle of Refraction $\sf{(sinr)}$ = ?

$\large\underline{\underline{\sf Solution:}}$

Let ,

speed of light in vaccum $\sf{(v_1)}$ = c

Speed of light in block $\sf{(v_2)}$ = $\sf{\frac{c}{\sqrt{2}}}$

According to Snell's Law :-

$\large{\boxed{\sf \frac{sini}{sinr}=\frac{v_1}{v_2} }}$

$\large\implies{\sf \frac{sin45°}{sinr}=\frac{c}{\frac{c}{\sqrt{2}}} }$

$\large\implies{\sf \frac{sin45°}{sinr}=\sqrt{2}}$

$\large\implies{\sf \frac{\frac{1}{\sqrt{2}}}{sinr}=\sqrt{2}}$

$\large\implies{\sf sinr=\frac{1}{2}}$

$\large\implies{\sf sinr=30° }$

$\Large\underline{\underline{\sf Answer:}}$

•°•Angle of Refraction is 30°