- #1
davidbenari
- 466
- 18
I have to questions that I can't seem to understand.
I've seen in my textbook the relation E=cB being deduced from Faradays law applied to some type of rectangular loop. The problem is this is done with regards to a planar wave. So is this relationship general for all EM waves? If so, how? And could someone show me a simple way to prove this to myself? If the velocity of a wave is not c but some other (because of refraction or whatever) then is the relation E=vB?
Another question I have is about electromagnetic energy density. Is the formula for EM energy density ##U=\frac{\epsilon E^2}{2} + \frac{B^2}{2\mu}## applied using the values for the magnetic and electric fields at a specific point? That is: similar to a problem with mass density, we assume small infinitesimal volumes in the neighborhood of a plane having the same energy density? (since the E and B values all have the same value at those points)
I've seen in my textbook the relation E=cB being deduced from Faradays law applied to some type of rectangular loop. The problem is this is done with regards to a planar wave. So is this relationship general for all EM waves? If so, how? And could someone show me a simple way to prove this to myself? If the velocity of a wave is not c but some other (because of refraction or whatever) then is the relation E=vB?
Another question I have is about electromagnetic energy density. Is the formula for EM energy density ##U=\frac{\epsilon E^2}{2} + \frac{B^2}{2\mu}## applied using the values for the magnetic and electric fields at a specific point? That is: similar to a problem with mass density, we assume small infinitesimal volumes in the neighborhood of a plane having the same energy density? (since the E and B values all have the same value at those points)