how fast does electricity travel

[marlonski]

If i were to send an electric signal, ie one morse code dot down a cable from the uk to australia how long would it take to recieve? What is the formula for calculating this speed? different conductors have different speeds i guess?

[TeeGee]

If the signal were strong enough to overcome the resistance in the wire over the whole distance then it could travel at, or near, the velocity of light. However, if there are any repeaters / amplifiers involved in the route then they would each individually insert a time lag. Normally, signals to faraway places go by satellite relay which not only increases the distance travelled but also includes a lot of electronics.
Typically, when speaking to Aus I experience a response delay of up to 2 seconds.

[Catso]

The theoretical speed of electricity is the speed of light. But in reality, it's always slower (it'd be impressive to be faster, wouldn't it?).

The resistance, capacitance and inductance of the conductor slows it down. The factor depends upon the conductor it is flowing through, so yes, different cable materials and constructions affect the speed.

Just to give you an idea, the factor usually varies in the range 0.60 - 0.90.

[marlonski]

Thanks for the reply but 0.6 to 0.9 what? is this a coefficiant of something?

[Catso]

If the cable coefficient is 0.6, the speed of leccy in it is 0.6 * <the speed of light>