Why does an electric current have a magnetic field?

Answer 1

A current carrying conductor, such as a metal wire, will produce a magnetic field around it because of the motion of charge within the wire itself. This motion produces or sets up a magnetic field around the wire in the form of concentric circles.

This electromagnetic effect is described in physics by the Biot-Savart Law, an experimentally deduced inverse-square law. The effect is also described by Ampère's Law, which is derived from the Biot-Savart Law. This law relates magnetic field and current.

Also, a magnetic field that is set up by an electrical current will produce a magnetic force. This force depends on the rate of charge transfer and the magnetic field.

The force produced by a current-carrying wire depends on the length, the magnetic field, and the current, which is the charge flow per unit of time.

Answer 2

Yes magnetic field could produce current but with a condition. The magnetic field has to change being linked with a conductor in the form of a coil or straight conductor. So important point is that the magnetic flux linked is to be changed. This could be done in three modes.

1) By changing the magnetic field ie by moving the bar magnets

2) By changing the area linked with magnetic field

3) By changing the orientation of a coil linked with a magnetic field.

Answer 3

A magnetic field can produce an electric field because the magnetic field and electric field are related by two constants the speed of light c and the free space impedance z:

E= cB = zH = zcD.

Answer 4

Because any electric charge, either positive or negative in motion produces a magnetic field around it. Ask God why...

Even in atoms, electrons turning around the nucleus and spinning on their axis produce a surrounding magnetic field. In most materials those fields cancel each other, except in some ones (magnets) where spinning is aligned somehow.

When electrons are forced to travel in one direction (DC current) they produce an steady magnetic field around the conductor. In the case of AC current an alternating magnetic field results, with an alternating frequency equal to the current frequency (usually 50 or 60 Hz depending on your location).

Radio transmission uses this principle except that higher frequencies are used, since the produced (electro) magnetic field around a cable (antenna) propagates to the surroundings and some of the radiated power can be catched at the receiving end.

If a lower frequency signal (like voice or sound) is superimposed on the current producing such field we have A.M. (Amplitude Modulation). If the low frequency signal adds or substracts to the the carrier frequency (i.e. the carrier frequency is modulated), then we have F.M. (Frequency Modulation) or as a variant of F.M., if the carrier frequency is shifted between two frequencies (one for 0's and other for 1's), we have FSK (Frequency Shift Keying) usually used to transmit digital data (or whatever, provided it is previously digitalized, like voice, music, images, video, etc.)

Answer 5

The answer is in Berkeley Physics Course, Electricity and Magnetism, vol. 2, by Ed. Purcell

Answer 6

Electric current is of heat energy and ionized particles (atoms), and so the field surrounding it has electromotive force of attracting or pulling or affecting other materials near it.

Answer 7

yes