A long narrow horizontal slit is placed 1 mm above a horizontal plane mirror. The interference between the light coming directly from the slit and that after reflection is seen on a screen 1.0 m away from the slit. Find the fringe-width if the light used has a wavelength of 700 nm.
Shane Macguire
12 Years agoGrade upto college level
1 Answer
Deepak Patra
12 Years ago
Sol. Given that, D = 1 m, λ = 700 nm = 700 * 10^–9 m
Since, a = 2 mm, d = 2a = 2mm = 2 * 10^–3 m (L loyd’s mirror experiment)
Fringe width = λD/d = 700 * 10^-9m * 1m/2 * 10^-3m= 0.35 mm.