Question

A ray of light is incident on glass slab making an angle of incidence $si{n}^{-1}\left(\frac{\sqrt{3}}{2}\right)$. What will be the angle of refraction in glass of refractive index 1.5?

• A. ${40}^o{18}^{\prime }$
• B. ${24}^o{49}^{\prime }$
• C. ${25}^o{17}^{\prime }$
• D. ${35}^o{16}^{\prime }$

Answer 1

Answer: (D)

${35}^o{16}^{\prime }$

Angle of incidence $i=si{n}^{-1}\left(\frac{\sqrt{3}}{2}\right)=si{n}^{-1}\left(sin{60}^o\right)={60}^o$

Using $\mu =\frac{sini}{sinr}$

$\Rightarrow sinr=\frac{sini}{\mu }=\frac{sin{60}^o}{1.5}=\frac{0.8660}{1.5}$

We get $sinr=0.5773$

Thus angle of refraction $r=si{n}^{-1}\left(0.5773\right)={35}^o{16}^{\prime }$