Show that in Young's double slit experiment for interference of light, the widths of the bright and dark fringes are equal.

In Young's double slit experiment what is the shape of interference fringes?

What is the effect on the interference pattern in Young's double slit experiment due to each of the following operations? The widths of the slits are increased equally.

In the Young's double slit experiment,the interference pattern is found to have an intensity ratio between brigth and dark fringe as 9.This i mplies that