A ray of light in air is incident on a glass slab at an angle of incidence of `60^(@)`. When it travels through glass, it is deviated through ` 15^(@)`. What is the refractive index of the material of the glass slab ?

Options

A. `1.275`
B. `1.225`
C. `1.8`
D. `1.5`

Answer

B

Explanation

Deviation of the ray ` delta=i-r :. 15^(@)=60^(@)-r :. r=45^(@)`
`:. n=(sin 60^(@))/(sin 45^(@))=((sqrt(3))/(2))/((1)/(sqrt(2)))=(sqrt(3))/(2) xx (sqrt(2))/1=sqrt((3)/2)=1.225`