The width of fringe is 2 mm on the screen in a double slit experiment for the light of wavelength of 400 nm . The width of the fringe for the light of wavelength 600 nm will be:

Step-by-step solution

For a light of wavelength λ , the fringe width in double slit experiment is given by β = λ D d       . . . ( 1 ) For a light of wavelength λ ' , the fringe width is given by β ' = λ ' D d       . . . 2 Divide equation (2) by equation (1) and simplify to obtain the fringe width for the later case. β ' β = λ ' D d λ D d =   λ ' λ ⇒ β ' =   λ ' λ β