# Electromagnetic waves

1. May 6, 2012

### polaris90

I have trouble understanding the concept of electromagnetic waves.
my textbook has the following explanation for electromagnetic momentum. It's not very clear to me.
[ light reflecting from a perfect reflector will leave the surface with its initial momentum, thus having twice its initial momentum.
Light being totally absorbed will have no momentum after absorption thus changing its momentum by its initial momentum.]
Since momentum is the product and mass of an object. How is this compared to electromagnetic momentum, what would be the mass in this case? My guess is the intensity of the wave. They also refer to it as just the electromagnetic radiation. Is their any difference?

2. May 7, 2012

### Bobbywhy

polaris90, Looks to me like each point you make and ask about are covered in a few short paragraphs on the wiki page: