其實光快還是電快?

Q: 電 在真空的環境下 的速度, 又是怎樣?
All electromagnetic waves have the same speed in vacuum, which is the speed of light (in fact, light itself is electromagentic wave in nature).

But the speed of electrical energy transfer is a different matter. Electricity transmitted in a copper wire is determined by the speed of propagation of the electric field. For a bare wire, this is about 96% of the speed of light in vacuum. The speed will be further reduced to 66% (of the speed of light) in a coaxial cable. This is due to the effect of the dielectrics surrounding the cable.

Q: 以光纖傳送訊號的速度, 及以電線傳送訊號的速度, 比較如何?
The speed of light is greatly reduced in a medium like glass. The actual speed depends on the refractive index of that medium material. For ordinary glass of refractive index 1.5, say, the speed of light in it is only 67% of that in vacuum.

Hence, the actual speed of transmission of light in a optical fibre is determined by the refractive index of the material of the optical fibre. In normal circumstances, if light is used to transmit signals through optical fibre, the speed of light, which now is the group velocity of the light wave, is even lower depending on the complexity of the signal.

電 在真空的環境下 的速度, 又是怎樣?
所謂電在真空中的速度,即是電子移動的速度?如果是,電子移動速度與電壓有關,電子可以移動得好快,也可以很慢,但電子一定唔會快過光速
還有, 以光纖傳送訊號的速度, 及以電線傳送訊號的速度, 比較如何?
光纖傳送訊號的速度比以電線傳送訊號的速度快,因為根據相對論,光速是宇宙中可以傳遞訊息中最快的速度