That means the electron is traveling at You may wonder how fast the electrons are whizzing around in the atoms around you. A good example and the most simple to calculate is the hydrogen atom which is in all our water. A calculation shows that the electron is traveling at about 2, kilometers per second. Read up on what happens when nothing can go faster than the speed of light. The time frames, in which electrons travel within atoms, are unfathomably short. For example, electrons excited by light change their quantum-mechanical location within mere attoseconds — an attosecond corresponds to a billionth of a billionth of a second.
But how fast do electrons whiz across distances corresponding to the diameter of individual atomic layers? Such distances are but a few billionths of a metre. To do so, the physicists applied a defined number of layers of magnesium atoms on top of a tungsten crystal. The researchers directed two pulses of light at these samples.
The first pulse lasted approximately attoseconds, at frequencies within the extreme ultraviolet. This light pulse penetrated the material and released an electron from a magnesium atom in the layer system as well as from an atom in the underlying tungsten crystal. Both the electrons that were set free stemmed from the immediate vicinity of the nucleus. Once released, the "tungsten electron" and the "magnesium electron" travelled through the crystal to the surface at which point they left the solid body.
There, the particles were captured by the electric field of the second pulse, an infrared wave train lasting less than five femtoseconds.
Category: Physics Published: February 19, The speed of electricity really depends on what you mean by the word "electricity". This word is very general and basically means, "all things relating to electric charge". 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. In the case of electrical currents traveling through metal wires, there are three different velocities present, all of them physically meaningful:.
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. Electric currents in metal wires are formed by free electrons that are moving.
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.
Electrons are really quantum entities, but the more accurate quantum picture is not necessary in this explanation. 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.
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. If a metal wire is left to itself, the free electrons inside constantly fly about and collide into atoms in a random fashion. Macroscopically, we call the random motion of small particles "heat". 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.
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. Now, if you connect the wire to a battery, you have applied an external electric field to the wire.
The electric field points in one direction down the length of the wire. 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 electrons continue to collide with atoms, which still causes them to bounce all around in different directions. But on top of this random thermal motion, they now have a net ordered movement in the direction opposite of the electric field.
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