If the two superimposing waves are of equal amplitude then the intensity of resultant wave will vary between as the phase difference changes from . The average intensity in space however remains the same as . Thus the superposition of waves results in redistribution of energy.

Fringe visibility: In the interference pattern, the intensity of the superimposed waves is redistributed in space between I_max and I_min . The points in space, where the intensity is more, will appear brighter than the point where the intensity is less. If the intensities I_max and I_min are very different, we can clearly see the interference fringes on screen.