A double-slit experiment is immersed in a liquid of refractive index `1.33`. It has slit separation of 1` mm` and distance between the plane of slits and screen is `1.33 m`. The slits are illuminated by a parallel beam of light whose wavelength in air is `6830 Å`. Then the fringe width is

Options

A. `6.3xx10^-4m`
B. `8.3xx10^-4m`
C. `6.3xx10^-2m`
D. `6.3xx10^-5m`

Answer

A

Explanation

The experimental setup is in a liquid, therefore the wavelength of light will change.
`lambda_(liquid)=(lambda_(air))/(mu)=(6300)/(1.33)`
`=(6300xx10^(-10))/(1.33)m`
Fringe width
`beta=(lambda_(liquid)D)/(d)=(lambda_(air)D)/(mud)=(6300xx10^(-10))/(1.33)xx(1.33)/(10^-3)`
`=6.32xx10^-4m`