Dispersion, Phase Velocity, Group Velocity

Description
Dispersive media is defined.Using the expressions for frequency for normal modes the velocity of the wave in a dispersive media is shown to be dependent on frequency.Frequency vs wave number graph is discussed. The idea of phase velocity and group velocity is introduced. Two simple slides show all the effects described in the theory. Dependence of phase velocity and group velocity on wavelength is discussed.

Prof. Walter Lewin, 8.03 Physics III: Vibrations and Waves, Massachusetts Institute of Technology: MIT OpenCourseWare),http://ocw.mit.edu (Accessed July 9 2011). License: Creative Commons BY-NC-SA: http://ocw.mit.edu/terms/#cc