In Young's experiment, the source is red light of wavelength `7xx10^(-7)m`. When a thin glass plate of refractive index `1.5` at this wavelength is put in the path of one of the intering beams, the central bright fringe shiffts by `10^(-3)m` to the position previously occupied by the `5^(th)` bright fringe.
When the source is now changed to green light of wavelength `5xx10^(-7)m`, the central fringe shifts to position initially occupied by the `6^(th)` bright fringe to red light. Find the refractive index of glass for green light.

Options

A. `1.4`
B. `1.2`
C. `1.6`
D. `1.3`

Answer

C

Explanation

Let `mu` be the refractive index for green light then
`Delta x = 6 lambda_(Red)`
`(mu - 1)t = 6lambda_(Red)`
`(mu - 1) = ((6)(7xx10^(-7)))/(7xx10^(-6)) = 0.6`
`mu = 1.6`