If the separation between the slits in a Young’s double slit experiment is increased, what happens to the fringe-width? If the separation is increased too much, will the fringe pattern remain detectable?

Question

Philoid · Accepted Answer

The fringe width in a Young’s double slit experiment is given by

Where D is the separation between the slits and the screen, is the wavelength of the light and d is the separation between the slits.

Hence if d increases, the fringe width decreases. If the separation is continuously increased, the fringes would lie in very close proximity of each other and would almost look uniform.