Electromagnetic Waves

Ehdrian

Hello,

This is not homework, as I'm not in school :)

I was wondering if there are any standard equations for electromagnetic waves interfering with each other. For instance, can I change the frequency of a wave by hitting it with another wave of a different frequency? I can find info on sound waves etc.. but I was wondering if this was any different.

The question I want to answer for myself is: "Can I get one lower frequency electromagnetic wave, by combining two or more higher frequency electromagnetic waves?"

Thank you :)