In Young's double slit experiment, the distance between two sources is `0.1mm`. The distance of screen from the sources is `20cm`. Wavelength of light used is `5460Å`. Then angular position of the first dark fringe is

Options

A. `0.08^(@)`
B. `0.16^(@)`
C. `0.20^(@)`
D. `0.32^(@)`

Answer

B

Explanation

`beta =(D)/(d) lambda=(20xx10^(-2)xx5.46xx10^(-7))/(10^(-4))=1.092xx10^(-3)m`
Distance of first dark badn `=0.5 beta`
Angular width `=(beta)/(D)=(0.5 beta)/(D)`
`=(0.5xx1.092xx0^(-3)xx180)/(20xx10^(-2)xx3.14)`
`=0.1564^(@)~~ 0.16^(@)`