http://www.ck12.org Chapter 15. Diffraction and Interference of Light
15.1 Double Slit Interference
- Define diffraction of light.
- Define wave interference.
- Describe double slit interference patterns.
- Explain Thomas Young’s contibutions to physics.
- Calculate the wavelength from a double slit interference pattern.
When waves strike a small slit in a wall, they create circular wave patterns on the other side of the barrier. This is
seen in the image above, where ocean waves create precise circular waves. The circular waves undergo constructive
and destructive interference, which generates a regular interference pattern.
Diffraction and Interference
When a series of straight waves strike an impenetrable barrier, the waves stop at the barrier. However, the last
particle of the medium at the back corner of the barrier will create circular waves from that point, called thepoint
source.This can be seen in the image below. This phenomenon is calleddiffraction, and it occurs in liquid, sound,
and light waves. While the waves become circular waves at the point source, they continue as straight waves where
the barrier does not interfere with the waves.