I read link given below:
Above link says
_The speed at which energy or signals travel down a cable is actually the speed of the electromagnetic wave, not the movement of electrons. Electromagnetic wave propagation is fast and depends on the dielectric constant of the material. In a vacuum the wave travels at the speed of light and almost that fast in air.
Since the velocity of propagation is very high — about 300,000 kilometers per second — the wave of an alternating or oscillating current, even of high frequency, is of considerable length. At 60 cycles per second, the wavelength is 5,000 kilometers, and even at 100,000 hertz, the wavelength is 3 kilometers. This is a very large distance compared to those typically used in field measurement and application._
It gives wavelength of EM wave in wire. How did they find it?
Edit : After reading comments
Also, why do you all say, it has nothing like that. That there is no such wavelength. Is Wikipedia wrong here then?
Edit 2 : I got that what wiki said was something different. They simply used $v = \lambda \nu$
Now, I wonder that electric field is caused by virtual photons. What is their frequency and wavelength in wire?