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. `10^(th)` bright
B. `10^(th) ` dark
C. `9^(th)` bright
D. `9^(th)` dark

Answer

B

Explanation

Path diff `=1.8xx10^(-5)-1.23xx10^(-5)`
`=0.57xx10^(-5)m`
Now, `n=("Path diff")/("Wavelenght")=(5.57xx10^(-5))/(6xx10^(-7))=9.5`
Thus, give points is `10^(th)` dark pioint.