Thomas Young's slit experiment confirmed that light travel as waves. The requirements are:
- 2 sets of waves
- both have same wavelength
- The phase difference must be constant
The interference caused from 2 slits overlapping diffracted beams.
Constructive interference make a bright fring, and destructive interference make a dark fringe.
Slit separation a, distance between the centers or edges of slits
Fringe separation x, distance between centers of adjacent bright or dark fringes
slit-to-screen distance D, distance from midpoint of the slits to the central fringe on the screen