A ray of light falls on a glass slab at an incident angle of `45^(@)` and refracted at angle of `30^(@)`.
What is the refractive index of the glass with respect to air ?

Explanation

Here, Medium 1 is air
Medium 2 is glass
Angle of incidence is `45^(@)`
Angle of refraction is `30^(@)`
Step 1: Refractive index of glass with respect to air `=(sin i)/(sin r)=(sin 45^(@))/(sin 30^(@))=(1//sqrt(2))/(1//2)=(2)/(sqrt(2))=(sqrt(2)xxsqrt(2))/(sqrt(2))=sqrt(2)`
Step 2: Since incident ray and emergent ray are parallel to each other, Angle of emergence (e)=Angle of incidence (i)
`therefore` Angle of emergence `(e)=45^(@)`