A ray of light travelling in impure water is incident on a glass plate immersed in it. Wher the angle of incidence is `51^(@)`, the reflected ray i totally plane polarised. Given that refractiv index of impure water is 1.4. The refractive index of glass should be ......

Options

A. `1.64`
B. `1.34`
C. `1.53
D. `1.73`

Answer

D

Explanation

`n= tan theta_(p)= tan51^(@)=1.235`
`n=(n_(g))/(n_(w)) rArr n_(g)=nxxn_(w)`
`=1.235xx1.4`
`=1.729`
`=1.73`