A beam of light of `lambda=600nm` from a distance source falls on a single slit `1mm` wide and the resulting diffraction pattern is observed on a screen `2m` away. The distance between first dark fringes on either side of the central bright fringe is

Options

A. (a) `1.2cm`
B. (b) `1.2mm`
C. (c) `2.4cm`
D. (d) `2.4mm`

Answer

D

Explanation

Given `D=2m`, `d=1mm=1xx10^-3m`
`lambda=600nm=600xx10^-6m`
Width of central bright fringe `(=2beta)`
`=(2lambdaD)/(d)=(2xx600xx10^-6)/(1xx10^-3)m`
`=2.4xx10^-3m=2.4mm`