Q10.7 In a double-slit experiment the angular width of a fringe is found to be 0.2° on a screen placed 1 m away. The wavelength of light used is 600 nm. What will be the angular width of the fringe if the entire experimental apparatus is immersed in water? Take refractive index of water to be 4/3.
Given
The angular width of the fringe when the medium is air
The distance of the screen from the slit
The wavelength of light we are using
Refractive index of water
let angular width of fringe when the medium is water
Now, as we know the angular width is given by
so,
From here
Hence angular width of the fringe in the water is .