All About Light
All About Light Main Page | Classical | Relativistic | Quantum
With this page, I start the non-quantum description of the light. ( For the quantum description, please see the Light in Quantum World page.)
How could this be light? These equations describe a propagating electromagnetic wave. Is light an electromagnetic wave?
Let's start with something everybody is familiar with, namely, waves on water.
If you disturb the surface of a body of water, (e.g., throwing a rock into a lake), you create waves that propagate on the surface of the water. We can easily measure their speed, amplitude and other properties. By watching the waves carefully, we conclude that the waves are nothing other than periodically moving water molecules spreading the initial disturbance of the water surface.
Similarly for sound (acoustic waves).
Sound is a periodically moving air molecules spreading the initial disturbance of the air (which might happen, for example when you blow a whistle).
But what is an electromagnetic wave?
Do we need a carrier for them? How do we create them? Please find the answers to questions like this on the next page.
|last modified 1/5/2001 email Fermilab|