In the adjoining figure, a wavefront AB moving in air is incident on a plane glass surface XY. Its position CD, after refraction through a glass slab is shown also along with the normals drawn at A and D. The refractive index of glass with respect to air will be equal to

Options

A. `(BD)/(AC)`
B. `(AB)/(CD)`
C. `(AB)/(AD)`
D. `(AC)/(AD)`

Answer

A

Explanation

`BD=v_(1) t, AC=v_(2) t`
`(sintheta)/(sinphi)=(BD//AD)/(AC//AD)=(BD)/(AC)=(v_(1)t)/(v_(2)t)=v_(1)/v_(2)=mu_(2)/mu_(1)`
`mu_(2)/mu_(1)=(BD)/(AC)`