Question

The Brewster angle for the glass-air interface is $54.74^{\circ}$. If a ray of light going from air to glass strikes at an angle of incidence $45^{\circ}$, then the angle of refraction is (given, $\tan 54.74^{\circ}=\sqrt{2}$ )

• A. $60^{\circ}$
• B. $30^{\circ}$
• C. $25^{\circ}$
• D. $54.74^{\circ}$

Answer 1

Answer: (B)

Refractive index $\mu=\tan \theta=\sqrt{2}$
Now according to snell's law
$\sqrt{2}=\frac{\sin (54.74)}{\sin r}$
$\sin r=\frac{0.816}{\sqrt{2}}\sin r=0.57$
$r=35^{\circ} \approx 30^{\circ}$