Two slits separated by a distance of 1 ~mm are illuminated with light of wavelength 6.5 10⁻⁷ ~m . The interference fringes are observed on a screen placed at 1 ~m from the slits. The distance between the third dark fringe and the fifth bright fringe is equal to

Step-by-step solution

Distance between two slit, d =1 ~mm =10⁻³ ~m Light of wavelength, =6.5 10⁻⁷ ~m Distance of screen from the slit, D=1 ~m For distance of dark fringe, y _ n = ( n - 1 2 ) D d take n =3 aligned & y₃= (3- 1 2 ) 6.5 10⁻⁷ 1 10⁻³ & = 5 2 6.5 10⁻⁴ & =16.25 10⁻⁴ ~m aligned For distance of bright fringe, y_n= n D d take, n =5 aligned & y₅= 5 6.5 10⁻⁷ 1 10⁻³ & =32.5 10⁻⁴ ~m & y₅-y₃=32.5 10⁻⁴-16.25 10⁻⁴ & =16.25 10⁻⁴ ~m & =1.625 ~mm . aligned