3 ms·
3blue1brown has recently released good YouTube videos on phase velocity. Question: how do I check group velocity in media, to know how fast information travers
by H8crilA 3y ago
3blue1brown has recently released good YouTube videos on phase velocity.
Question: how do I check group velocity in media, to know how fast information traverses through that media? For example in water - how long does it take for my waterproof flashlight to get across a small body of water? As in where to find that information. I always thought I just have to look up the index of refraction, but that's just the phase velocity.
- pfedak 3y agoThe index of refraction (including its dependence on frequency) fully describes the physics, there's nothing else to look up. Group velocity is a derived property taking into account the mathematics of waves, and in the typical textbook example of a very-nearly-monochromatic wave can be computed from the derivative of the index of refraction with respect to frequency.