In Young's double slit experiment the wavelength of light used is 6000 Å , the screen is 40 cm from the slits and the fringe width is 0.012 cm , the distance between two slits is

Step-by-step solution

The fringe width in Young's double-slit experiment is determined by the relation β = D d , where λ is the wavelength, D is the screen distance, and d is the slit separation. Given values are wavelength λ = 6000 = 6 10⁻⁷ m , screen distance D = 40 cm = 0.40 m , and fringe width β = 0.012 cm = 1.2 10⁻⁴ m . Solving for the slit separation yields d = D β = (6 10⁻⁷) 0.40 1.2 10⁻⁴ = 2 10⁻³ m . Converting to centimeters gives d = 0.2 cm , which corresponds to option D .