A ray of light incident at `49^(@)` on the face of an equilaternal prism passes symmetrically. Calculate the refractive index of the material of the prism.

Explanation

As the prism is an equilateral one, `A = 60^(@)`. As the ray of light passes symmetrically, the prism is in the position of minimum deviation.
So, `r=A/2=60^(@)/2=30^(@)`
also, `i=49^(@)`
`:. mu=(sin i)/(sin r)=(sin 49^(@))/(sin 30^(@))=0.7547/0.5=1.5`