Why does power transfer at light speed but electron drift velocity is much slower?

[kiamzattu]

Hi
I've a small doubt regardin the speed of power transfer.v know tat electric current produces electric and magnetic field around it. So is it an EM wave? if its so then it should travel at velocity of light right? on the other hand the speed of electrons in a conductor is around 10^6 m/s. since motion of electrons is current, what is d actual speed of current? is it d velocity of light or speed of electrons?

Regards
Anand

 

[Astronuc]

The 'current' is related to the speed of the electrons (and their charge) in the wire.

Each charge produces an electric field, and a moving charge (current) produces a magnetic field. Electric and magnetic fields propagate at the speed of light.

A 60 Hz oscillation would produce a varying EM field of 60 Hz, which is very, very low frequency. Consider AM radio is hundred of kHZ (or 0.5 - 1.7 MHz), FM radio is (~88-107) MHz, and microwave is on the order of GHz.