MAXWELL'S EQUATION CONTINUED

MAXWELL’S EQUATIONS CONTINUED These are equations which the field vectors E,D,B and H everywhere Satisfy. These equations are called Maxwell’s equation They are div D =ρf div B =0 Curl E = -dB/dt Curl H = jf + dD/dt Any possible electromagnetic field must satisfy all of Maxwell’s equation For isotropic and homogeneous materials of interest, D=εεoE H=B/μμo ε - Relative permittivity μ - Relative Permeability They both depend on frequency. This is the case in principle for all parameters which describe the macroscopic behavior of media in electric and magnetic fields. When you consider the equation of continuity and charge conservation, Since charge is conserved, this charge must be equal to the change in the total charge within the volume element. (dρ/dt)dtdτ = -divjdτdt dρ/dt + divj = 0 This derivation of this equation is independent of the position of the volume element. Hence the relation holds at all points and at all times. The equation above is the equation of continuity, expressing the conservation of charge in differential form. Note that this is for steady current not for when currents are changing with time.