Question

A transparent medium shows relation between i and r as shown. If the speed of light in vacuum is c the Brewster angle for the medium is

• A. $60^\circ$
• B. $30^\circ$
• C. $90^\circ$
• D. $45^\circ$

Answer 1

Answer: (A)

$By\, Brewster’s \,law, n=tan \, \theta_{p} $
$Also\, n=\frac{sin \, i}{sin \, r}$
$But\, \frac{sin\,i}{sin\,r}=\frac{1}{slope} \, of \,given \,graph$
$\frac{sin\,i}{sin\,r}=\frac{1}{tan\,30^{\circ}}=\frac{1}{\frac{1}{\sqrt{3}}}=\sqrt{3}$
$\therefore \, tan \, Q_{p}=n=\sqrt{3}$
$Q_{p}=tan^{-1}\left(\sqrt{3}\right)=60^{\circ}$