Double Slit Interference [IB Physics SL/HL]

This video explains the formation of two-source interference patterns from Theme C of the IB Physics SL & HL courses. After the concept of coherent sources is introduced, the interference of waves from two sources is explored with reference to the difference in path length from a point to the two sources. Locations of constructive and destructive interference are identified and the formation of the interference pattern is shown. Young's double-slit experiment is then introduced, with the concept of path length difference again applied to the formation of bright and dark fringes. The formula relating the fringe spacing to the wavelength of light, screen distance, and slit separation is then discussed.

0:00 Introduction
0:24 Coherent waves
1:40 Two-dimensional interference
3:26 Destructive interference
4:49 Young’s double slit experiment
6:51 Fringe spacing
10:30 Summary

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