A long narrow horizontal slit is placed 1 mm above a horizontal plane mirror. The interference between the light coming directly from the slit and that after reflection is seen on a screen 1.0 in away from the slit, Find the fringe-width if the light used has a wavelength of 700 nm.

Answer

C

Explanation

Givent that `D=1m`
`lamda=700mm=700xx10^-3m
Since `a=1mm`
`d=2a=2mm`
`=2xx10^-3m`
[L loyd's mirror experiment]`
Fringe width =(lamdaD)/d`
`=(700xx10^9xx1m)/(2xx0^-3m)`
`0.35mm`