Group Velocity

The group velocity of a wave is the velocity with which the variations in the shape of the wave's amplitude (known as the modulation or envelope of the wave) propagate through space. For example, imagine what happens if you throw a stone into the middle of a very still pond. When the stone hits the surface of the water, a circular pattern of waves appears. It soon turns into a circular ring of waves with a quiescent center. The ever expanding ring of waves is the group, within which one can discern individual wavelets of differing wavelengths traveling at different speeds. The longer waves travel faster than the group as a whole, but they die out as they approach the leading edge. The shorter waves travel slower and they die out as they emerge from the trailing boundary of the group.
See more at Wikipedia.org...

1. The velocity of propagation of an envelope produced when an electromagnetic wave is modulated by, or mixed with, other waves of different frequencies. (188 ) Note: The group velocity is the velocity of information propagation and, loosely, of energy propagation. 2. In optical fiber transmission, for a particular mode, the reciprocal of the rate of change of the phase constant with respect to angular frequency. Note: The group velocity equals the phase velocity if the phase constant is a linear function of the angular frequency, = 2f , where f is the frequency. 3. In optical-fiber transmission, the velocity of the modulated optical power.

B: (Fisika) kecepatan kelompok
Built to Babylon by Hikmat Gumilar Visit my Website;    

Eng: group velocity
Urdu: رفتار مجمُوعہ امواج ۔