Vector Field Visualization
https://www.geogebra.org/m/QPE4PaDZ

E is the electric vector
B is the magnetic induction
ρ is the electric charge density
j is the electric current density
ε0 is the permittivity of free space
ε is the dielectric constant (or permittivity)
c is the speed of light
σ is the specific conductivity
μ is the magnetic permeability
j=σE
D=εE D is the electric displacement
B=μH H is the magnetic vector
Maxwell Equations
Gauss’s law
Divergence of electric field is proportional to the charge density inside volume
This is an abuse of notation
This has abuse of notation
is the outward pointing unit normal at each point on every on the boundary of surface S of Volume V
Gauss’s law for magnetism
The magnetic field B has divergence equal to zero. It is equivalent to the statement that magnetic monopoles do not exist.
This is an abuse of notation
Faraday’s law of induction
A circulating electric field is produced by a magnetic field that changes with time.
Curl of E , the circulation of electric field , around an axis perpendicular to each plane at point (x,y,z) is equal to the rate of change in magnetic field
This is an abuse of notation
AmpereMaxwell Law
A circulating magnetic field is produced by an electric current and by an electric field that changes with time.
This is an abuse of notation
Curl of B , the circulation of magnetic field , around an axis perpendicular to each plane at point (x,y,z) is proportional to the rate of change in Electric field + electrical current
if J=0 then
Deriving Electromagnetic waves from Maxwell’s equations https://www.youtube.com/watch?v=LsXjVfucHU
https://web.mit.edu/sahughes/www/8.022/lec20.pdf
https://en.wikipedia.org/wiki/Displacement_current
https://physics.stackexchange.com/questions/166888/thepropagationofelectricfield
Book: https://matterandinteractions.org/
Liénard–Wiechert potential classical electromagnetic effect of a moving electric point charge
What is the proof of the BiotSavart law from Maxwell equations
https://www.khanacademy.org/science/ininclass12thphysicsindia/movingchargesandmagnetism
Magnetic field of a moving charge
میدان و امواج
Feynman
Full https://www.youtube.com/watch?v=kExgRfuhhk
Richard P Feynman: Quantum Mechanical View of Reality – YouTube
QED:New Queries (Richard Feynman 4/4) – YouTube
QED: Electrons and their Interactions (Richard Feynman 3/4) – YouTube
Explanations
This relates to electric field in that the charge moving through a circuit to light a light bulb has to be driven by some electric field, so you can reasonably ask how that field is established, and how much time it takes. Qualitatively, the necessary field is established by excess charge on the surface of the wires, with the surface charge being generally positive near the positive terminal of a battery and generally negative near the negative terminal, and dropping off smoothly from one to the other so that the electric field is more or less piecewise constant (that is, the field is the same everywhere inside a wire, and the field is the same everywhere inside a resistor, but the two field values are not the same).
When the circuit is first connected, there is a rapid redistribution of the charge on the surface of the wires which establishes the surface charge gradients that drive the steadystate current that will eventually do whatever it is you want it to do. The time required to establish the gradients and settle in to the steadystate condition is very fast, most likely on the order of nanoseconds for a normal circuit.
Since 11 April 2023: 779 total views, 17 views today