電子的速度快D定係光速快D

Q1: The eletron's speed can be vary, in the particle accelartor, the electron can be accelerate to near the speed of light (c). While in the wire at your home, it is a few cm/s. If you mean the electrical signal in the wire (That is, the speed when you switch on the light and the light on), this speed is same as light speed (c). The speed of electron is not relative the the speed of the electrical signal. That is when the generator generates electricity, you can recieve it at you home immediately.

Q2: Refer to the above.

Q3: We use 300000000m/s in calculation (vaccumn). You can search the exact value on web. If you know refractive index n, then the speed of light (c) in a medium is c/n, where n is the refractive index.

Q1:電子的速度一定比光速慢
Q2:電子速度通常係光速2/3
Q3:光速的速度係299792458m/s (speed of light in vacuum)
希望解答到你 ^^