Biprism experiment is conducted with a wavelength of `5000Å`. The distance between the virtual sources is 0.2 mm and the micrometer eyepiece is at a distance of 100 cm from the slits. The distance between the consecutive bright and dark between the consecutive bright and dark band is

Options

A. `1.25 mm`
B. `2.5 mm`
C. `3.5 mm`
D. `0.25 mm`

Answer

A

Explanation

`lambda 5000A^(@), d=0.2 mm D=1 m, beta = ?`
`beta =(D)/(d) lambda`
`=(1xx5xx10^(-7))/(0.2xx10^(-3))`
`25xx10^(-4)`
`=2.5 mm` b
Thus distance between consecutive bright and dark band is `(beta)/(2)=(2.5)/(2)=1.25 mm`