The width of fringe is 2mm on the screen in a double slits experiment for the light of wave length of 400nm. The width of the fridge for the light of wavelength 600nm will be

In a double-slit experiment, the fringe width (β) is directly proportional to the wavelength (λ) of the light used. This relationship is expressed by the formula:

β = (λ × D) / d

where:

• β is the fringe width,
• λ is the wavelength of light,
• D is the distance between the slits and the screen,
• d is the distance between the two slits.

Given that the initial fringe width is 2 mm for a wavelength of 400 nm, we can determine the new fringe width for a wavelength of 600 nm by calculating the ratio of the wavelengths:

New fringe width = Initial fringe width × (New wavelength / Initial wavelength)

Substituting the given values:

New fringe width = 2 mm × (600 nm / 400 nm)

Since 600 nm / 400 nm = 1.5:

New fringe width = 2 mm × 1.5 = 3 mm

Therefore, the fringe width for the light of wavelength 600 nm will be 3 mm.

This calculation demonstrates that increasing the wavelength of light used in a double-slit experiment results in a proportional increase in the fringe width, leading to wider interference fringes on the observation screen.