The distances of a point on the screen from two slits in biprism experiment is `1.8xx10^(-5)` m and `1.23xx10^(-5)` m if wavelength of light used is 6000 Å then fringe formed at that point is

Options

A. `8^(th)` dark
B. `9^(th)` dark
C. `10^(th)` dark
D. `11^(th)` dark

Answer

C

Explanation

Path diff. `=1.8xx10^(-5)-1.23xx10^(-5)`
`=0.57xx10^(-5) m`
Now, `n= ("Path diff.")/("Wavelength")= (0.57xx10^(-5))/(6xx10^(-7))=9.5`
Thus, given, point is `10^(th)` dark point.