A glass sheet `12xx10^(-3)` mm thick `(mu_(g)=1.5)` is placed in the path of one of the interfering beams in a Yongs's double slit interference arrangement using monochromatic light of wavelenght 6000 A. If the central bright fringe shifts a distance equal to width of 10 bands. What is the thickness of the sheet of diamond of refractive index 2.5 that has to be introduced in the path of second beam to bring th ecentral bright fringe to original position?

Options

A. `20//9 mum`
B. `7.2 mum`
C. `3 mum`
D. `4 mum`

Answer

D

Explanation

Now, to bring the central fringe back to the original position.
`t_(g)(mu_(g)-1)=t_(-0)(mu_(0)-1)rArrt_(D)=4xx10^(-6)m=4mum`