Discussion Forum



1)

 The Brewster's angle for the glass-air interface is (54.74) °. If a ray of  light passing from air to glass strikes at an angle of incidence 45°, then the angle of refraction  is

  $[\tan (54.74)^{0}=\sqrt{2},\sin 45=\frac{1}{\sqrt{2}}]$


A) $\sin ^{-1}\left(\sqrt{2}\right)$

B) $\sin ^{-1}\left(1\right)$

C) $\sin ^{-1}\left(0.5\right)$

D) $\sin ^{-1}\left(\frac{0.5}{\sqrt{2}}\right)$

Answer:

Option C

Explanation:

According  to Brewster'law , refarctive index of glass

$\mu_{2}=\tan(i_{p})$

 = $\tan (54.74)^{0}$= $\sqrt{2}$

 From Snell's law,

$\mu_{1}\sin i=\mu_{2}\sin r$

 $1\times \sin(45^{0})=\sqrt{2}\sin r $

$\frac{1}{\sqrt{2}\times\sqrt{2}}=\sin r$

 sin r=0.5

    r = sin-1 (0.5)