Question

please any one,explain me the displacement current?

Answer 1

It is the current that arises from a changing E field, however any chanign E field has a corresponding B field change, so it isn't a physical current in the sense that it isn't a stream of charged particles moving rather it is "psuedo-current". The way to arrive at is by differentating w.r.t to time the electric displacement field\[D=\epsilon_{o}E + P\]
Please noe that D, E and P, are vectors( I have no clue how to make them bold the normal Latex code isnt working). You arrive at

\[J=\epsilon\frac{\delta E}{\delta dt} +\frac{\delta P}{\delta dt} \]
Again notice that they are all vectors.

You can also arrive at it by considering if you are in Free Space, simply the curl of B. Remenber that the \[\nabla\times B=\mu J +\mu\epsilon\frac{\delta E}{\delta dt} \]

Answer 2

While studying how energy was stored in a capacitor/dielectric, Maxwell came up with the idea/theory that the energy was stored in the stretching of the atoms of the material. The larger the electric field, the more the atoms were stretched, and when the electric field was removed, the atoms snapped back to their original state, giving up the energy that was stored in them.

Answer 3

This further led him to the insight that if atoms become stretched when an electric field is applied, then when the electric field is changing in time, it must induce a current. This must be so because when an atom becomes more stretched by the increasing electric field, its positive charge moves in the direction of the applied electric field while its negative charge moves in the opposite direction. But this means that both moving charges contribute to current flow in the direction of the applied electric field. This current, Maxwell realized, must produce magnetic field, and hence should be added to the conduction current in Ampere's law. He called this current displacement current.

Answer 4

what is its defination?

Answer 5

He gave the formula for the displacement current flowing through a surface as:
dΦE
Id = co ------
dt
where ΦE is the electric flux through the surface.

This formula can be used to find the total amount of displacement current flowing through a surface.
The physical meaning of this displacement current is that a changing electric field makes a changing magnetic field. To find the direction of the magnetic field produced by this effect we use our usual right-hand rule for currents.

Answer 6

In electromagnetism, displacement current is a quantity that is defined in terms of the rate of change of electric displacement field. Displacement current has the units of electric current density, and it has an associated magnetic field just as actual currents do.

Answer 7

Hi Astronomer, I use the bar above the letters to denote vectors, in lieu of equation boldface