A ray of light incident on an equilateral glass prism of refractive index $μ=\sqrt{3}$, travels parallel to the base of the prism inside it. What is the angle of incidence for this ray?

60°

The correct answer is Option (4) → 60°

For an equilatoral angle, angle of prism (A) = 60°

At minimum deviation $(r_1=r_2)$ and -

$A=2r$

$⇒r=\frac{A}{2}=30°$

$∴μ_{air}\sin i=μ_{medium}\sin r$ [Snell's law]

$⇒\sin i=\sqrt{3}.\frac{1}{2}=\frac{\sqrt{3}}{2}$

$i=60°$