Question

(6) With the aid of an appropriate diagram, show that for Young's double slit experiment, y = 2. D/a, where 2 is the wavelength of the source, a is the slit separation, D is the distance between the slits and the screen, and y is the separation between the central bright fringe and the first order fringe. (c) In Young's double slit experiment, the slit spacing was 0.56 mm and the distance across the four-fringe spacing was 3.6 mm when the screen was at a distance of 0.8 m from the slits. (i) Calculate the wavelength of the monochromatic light used in this experiment. (ii) On a suitable sketch, indicate the intensity variation of the fringes from the central maximum to the fourth bright fringe.

Answer 1

S, SLIK*** let Slets S, and S, have seperation a and the distance between slits and screen iso. For the rays traveling a be the path difference so X = al sino For bright fringe path difference should be integral multiple of t * asino=nd ² Sino = nl Now tano = a For first order. sino = e = n=1 Som now take o is very small so we can Sino ~ tano - Screen >> Tycho LC - 3.6X10-3x0.56 x 10-3 = ya s - 4 x 0.8 y = 6:3x10-17 m Intensity vanatım is I - 41. sind, (d) ulo ДДДИЛА -SM -41 -31 - 21 IT T 217 317 ute