(N/A) Young's double slit experiment consists of a monochromatic light source illuminating a single narrow slit $S$ on screen $A$.
This light then falls on two parallel,narrow slits $S_1$ and $S_2$ located on screen $B$,which are equidistant from $S$ (i.e.,$SS_1 = SS_2$).
These two slits act as coherent sources of light. When the light waves emanating from $S_1$ and $S_2$ superimpose on a distant screen $C$,they produce an interference pattern consisting of alternating bright and dark fringes.
The intensity distribution curve shows that all interference fringes have the same width and intensity. Points where destructive interference occurs have zero intensity,while points of constructive interference have maximum intensity $I_{max}$.
The distance between two successive bright fringes or two successive dark fringes is constant,and the fringe intensity is independent of the fringe order.