why cant we use electromagnetic fileds to transfer current?

Question

Why cant we use electromagnetic fields to produce current in a distant conductor. whenver a EM wave is incident on a conductor a surface current flows in the conducto. what is the magnitude of the current for an ordinary cell phone wave. and what is equation governing this current density if we have the magnetic field? If this is not possible I need some reasons.

Answer 1

We do use electromagnetic fields to transfer current. Every day.

It's a necessity in the power industry! The device is called a "transformer".

The major limitation for use is dependent on both the strength of the originating magnetic field and the distance to the conductor which is have current induced. The resultant current is less, in proportion to the square of the distance between the conductor and the field source. It is also less in proportion to the magnitude of the originating field.

The actual induced current is achieved by passing a conductor through a stationary magentic field (in which case the frequency of the current waveform is proportional to the speed of the conductor's movement), or by oscillating the magnetic field at some frequency compared to a stationary conductor (in which case the frequency of the current is the same as the magnetic oscillation frequency), or by a combination of the two.

Believe it or not, this is exactly how rotating electrical machines work. Alternating Current machines vary the magnetic field in the stator using an AC waveform for stator current (and induce currents in rotor components). Direct Current machines mechanically induce an alternating field in the rotor by rotating the conductors through a fixed magnetic field.

Answer 2

Part of the problem is, electromagnetic fields decrease in intensity with the square of the distance. This is possible think about a CdS solar cell, it converts EM radiation into an electric current. However, the sun is one hell of a light bulb.

Answer 3

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Answer 4

I think you are referring to induction.

It is possible to create a current in a wire or other object through induction, although it is not practical in may applications. It is used in some rechargable appliances (such as toothbrushes) though.