光纖比銅線有何優點？

Q: 在通訊方面，光纖比銅線有何優點？
Optical fibre is advantageous for long distance communications because light propagates through the fibre with little attenuation (could be as low as 4 dB/km) compared to electrical cables. This allows long distance to be spanned with few repeaters.

Because light is used in optical fibre for comunication, the wavelength of light is much much shorter than microwave. This allows more channels to be built in in using optical fibres than in copper cables. The bandwidth for each channel could also be increased, thus enabling more data to be transmitted.

Q: 電在銅線中的傳輸速度是多少？
The transmission speed of electricity in copper cables is the same as the speed with which electric field along the cable is set up. For copper, this is about the speed of light.