The interesting thing is that when an electron moves, its field moves with it, so that the electron can push another electron farther down the wire through its field long before physically reaching the same location in space as this electron.
The closer two electrons get to each other, the stronger they repel each other through their electromagnetic fields. Rather, electrons interact through the electromagnetic field. They do not interact with each other by literally knocking into each other's surfaces. The average speed at which the electrons move down a wire is what we call the "drift velocity".Įven though the electrons are, on average, drifting down the wire at the drift velocity, this does not mean that the effects of the electrons' motion travels at this velocity. An applied electric field (such as from connecting a battery) therefore causes an electric current to flow down the wire. The electric current in the wire consists of the ordered portion of the electrons' motion, whereas the random portion of the motion still just constitutes the heat in the wire. But on top of this random thermal motion, they now have a net ordered movement in the direction opposite of the electric field. The electrons continue to collide with atoms, which still causes them to bounce all around in different directions.
The free electrons in the wire feel a force from this electric field and speed up in the direction of the field (in the opposite direction, actually, because electrons are negatively charged). The electric field points in one direction down the length of the wire. Now, if you connect the wire to a battery, you have applied an external electric field to the wire. A wire left to itself carries no electric signal, so the individual electron velocity of the randomly moving electrons is just a description of the heat in the wire and not the electric current. The actual speed of an individual electron is the amount of nanometers per second that an electron travels while going in a straight line between collisions. Macroscopically, we call the random motion of small particles "heat".
If a metal wire is left to itself, the free electrons inside constantly fly about and collide into atoms in a random fashion. Each free electron in the metal wire is constantly flying in a straight line under its own momentum, colliding with an atom, changing direction because of the collision, and continuing on in a straight line again until the next collision. (When you add in quantum effects, the individual electron velocity becomes the "Fermi velocity".) The non-free electrons, or valence electrons, are bound too tightly to atoms to contribute to the electric current and so can be ignored in this picture. Electrons are really quantum entities, but the more accurate quantum picture is not necessary in this explanation. In the context of typical electric currents in metal wires, free electrons can be thought of as little balls bouncing around in the grid of fixed, heavy atoms that make up the metal wire. Electric currents in metal wires are formed by free electrons that are moving. In order to understand each of these speeds and why they are all different and yet physically meaningful, we need to understand the basics of electric currents. In the case of electrical currents traveling through metal wires, there are three different velocities present, all of them physically meaningful:
I will assume we are referring to a current of electrical charge traveling through a metal wire, such as through the power cord of a lamp. This word is very general and basically means, "all things relating to electric charge". The speed of electricity really depends on what you mean by the word "electricity". Public Domain Image, source: Christopher S. Time is equal Distance/Speed.Electromagnetic energy and information travel down a wire at close to the speed of light. Time Speed Distance Formulaĭistance is equal to speed × time. You'll receive the result in standard time format (HH:MM:SS). For distance, you should enter its value and also select the proper length measurement unit from the scroll down menu. For the speed, you need to enter its value and select speed unit by using the scroll down menu in the calculator. Therefore, in order to calculate the time, both distance and speed parameters must be entered. This online calculator tool can be a great help for calculating time basing on such physical concepts as speed and distance.