In Young's double slit experiment, the 10th bright fringe is at a distance x from the central fringe. Then
a) the 10th dark fringe is at a distance of `19x//20` from the central fringe
b) the 10th dark fringe is at a distance of `21x//20` from the central fringe
c) the 5th dark fringe is at a distance of `x//2` from the central fringe.
d) the 5th dark fringe is at a distance of `9x//20` from the central fringe.

Options

A. a,b,c only
B. b,c,d only
C. a,d only
D. a,b,c,d only

Answer

C

Explanation

`Y_(bright) = y_(n) = n ((lambda D)/(d))`
`y_(dark) = y_(n) = (2n - 1) (lambda D)/(2d) , Where n = 1,2,3,4`