In a Young's double slit experiment, a laser light of 560 nm produces an interference pattern with consecutive bright fringes' separation of 7 . 2 mm . Now another light is used to produce an interference pattern with consecutive bright fringes' separation of 8 . 1 mm . The wavelength of second light is _____ nm .

Step-by-step solution

Given here: λ 1 = 560 × 10 - 9   m , β 1 = 7 . 2 × 10 - 3   m and β 2 = 8 . 1 × 10 - 3   m . Let d be the width and D be the distance between slit and screen then fringe width, β = λ D d . Thus, from above, β ∝ λ So, the wavelength of second light is λ 2 = β 2 β 1 λ 1 = 9 8 λ 1 ∴       λ 2 = 9 8 × 560 = 630   nm .