I am a reading a book on electromagnetism and I read the following relations:
- For electric intensity and field density:
The flux density D is *independant* of the medium whereas the intensity E is *dependant* on the medium. This is captured by the equation:
D = eE; where e is the permittivity of the medium.
- For magnetic intensity and field density:
The flux density B is *dependant* on the medium whereas the intensity H is *independant* of the medium. This is captured by the equation:
B = uH; where u is the magnetic permeability of the medium.
I would like to know:
Q1. Why this difference in approach between the electric and magnetic fields. Why can't we have both the intensties to be independant (or dependant) on the medium or vice-versa?
Q2. Why have two distinct notions (for both electric and magnetic field):
- Intensity vector and, 2. Flux density vector? (Especially when both the notions indicate the same thing - the intensity of the field at a point.)