###### Asked in Cameras, Electricity and Magnetism
Cameras
Electricity and Magnetism

# What is the average speed of electricity?

## Answer

###### 04/07/2017

There are three different speeds here.The average speed of electrons - whether there is a current or not - is a significant fraction of the speed of light. That speed depends on the temperature. (The average VELOCITY of course is zero if there is no current, since as many electrons will go in one direction as in another.)

The drift velocity (the average velocity) of the electrons is a small fraction of a millimeter per second. The exact value depends on the current, the cross section, and the material.

The speed at which a signal can propagate in copper is about 2/3 of the speed of light in a vacuum - so, about 200,000 km/second. It is this speed that makes your light react quickly when you activate a switch.