In Young's double slit experiment the ratio of phase difference between light waves reaching the third bright fringe and third dark fringe is

Step-by-step solution

In Young's double slit experiment, the path difference x for the n -th bright fringe is given by x = n , where n = 0, 1, 2, . The phase difference is related to the path difference by = 2 x . For the third bright fringe, n = 3 . Thus, the path difference is x_ bright = 3 . The phase difference for the third bright fringe is _ bright = 2 3 = 6 . The path difference for the n -th dark fringe is given by x = (2n - 1) 2 , where n = 1, 2, 3, . For the third dark fringe, n = 3 . Thus, the path difference is x_ dark = (2