Thread: Electromagnetic Radiation

Hi,

I'm confused about electromagnetic radiation. What does it mean to say the magnetic wave and the electric wave travel at 90 degrees to each other?

basically the planes in which the two waves oscillate are at 90 degrees to eachother.

What does "plane" mean here?

Also, how can the magnetic wave be 90 degrees to the electric field AND the line of progress of the wave?
As the electric field is already at 90 degrees to the direction of movement, surely the magnetic field has to be either oscillating in the same direction as the movement or at 180 degrees to the direction of the movement?

I know the above paragraph must be wrong, so please help if you can!

http://www1.union.edu/newmanj/lasers...es/e&mWave.gif

Janus, that diagram is amazing! Why is that not in EVERY textbook? It makes the concept so clear.

Thanks very much.

Originally Posted by russell_c_cook

Janus, that diagram is amazing! Why is that not in EVERY textbook? It makes the concept so clear.

Thanks very much.

What introductory textbook are you reading that does not have such a diagram ?

Originally Posted by DrRocket

What introductory textbook are you reading that does not have such a diagram ?

I confess I find myself asking the same question. When I read Russel's OP the essence of that diagram sprung into my mind. It seems very basic and I doubtless picked it up many decades ago in an elementary textbook (since elementary is all I've ever managed with physics).