Path: utzoo!mnetor!uunet!mcvax!ukc!stc!idec!alice!malcolm
From: malcolm@alice.marlow.reuters.co.uk (Malcolm Melville)
Newsgroups: sci.misc
Subject: Wave and Group Velocity
Message-ID: <251@alice.marlow.reuters.co.uk>
Date: 19 Feb 88 21:52:19 GMT
Organization: Reuters Ltd, London, England
Lines: 20

Just read the stuff on the difference between sound and light waves and
it reminded me that I was always confused by this concept of wave and group
velocities. It was explained to me one time using the model of a pair of
scissors closing. The intersection point of the blades moves rapidly and
is like the group velocity. The points of the blades are real physical points
and move slower abd are like the wave velocity. (I told you I didn't ever
unerstand this stuff.)
Does this mean that the group velocity is always larger than the wave velocity?
Is it true that the group velocity can be greater than the speed of light??
How does this affect me??

All explainations welcome!!

Malcolm

-- 
The views expressed are my own rather than my employers. Mind you
lots of other guys round here feel the same way.

Malcolm Melville