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free charge
noun
- any electric charge that can be placed on a conductor or on or within a dielectric or that moves freely in space ( polarization charge ).
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More About Free Charge
What is a free charge?
A free charge is an electric charge that can move freely in space.
In atoms, there are tiny particles known as protons and electrons. These particles are said to have electric charges, a property that allows them to cause a wide variety of interactions with other particles that also have charges.
A proton is said to have a positive charge. It doesn’t move very much and mostly stays in the nucleus of an atom. An electron has a negative charge. It can orbit the nucleus and is able to move more freely. We usually describe the movement of electrons as resembling shells around the nucleus.
In some substances, the electrons have a large amount of freedom to move around. Electrons within metals, for example, move freely and can flow into an outer shell or even to another atom. Substances that have freely moving electrons like this are said to have a free charge.
The opposite of a free charge is a polarization charge, or a bound charge. This kind of charge occurs when electrons are tightly bound to the nucleus and don’t move nearly as much.
Why is free charge important?
The term free charge, referring to electricity, has been used since at least the 1890s. It is often used in complicated analysis and calculations involving electromagnetism and electric fields.
Did you know … ?
Metals conduct electricity easily because of their free charge from their freely moving electrons. The metals’ electrons are free to flow and interact with any positive charges that attract them.
What are real-life examples of free charge?
This image shows a lithium atom’s protons, neutrons, and electrons. As you can see, the outer electrons move freely in space.
Lithium Bohr Diagram:
3 Proton
3 Electron
4 Neutrons pic.twitter.com/qw4ihxWqAb— Lithium [Li] (@chemistry213) September 22, 2016
The term free charge is used in advanced analysis and discussion of electricity and electromagnetism.
Today in PHYS 302: Bound vs free charge distributions, the D field, and Gauss's law in dielectric materials. Don't miss it!
— Brian Bunton (@brianbunton) September 25, 2012
Free charges in a plasma can annihilate external electric fields: if an electromagnetic wave is injected onto a plasma, electrons can repel the wave's electric field (if there's a sufficient number of them) resulting in reflection (e.g. radio waves at ionosphere).#PlasmaThursday
— Alf Köhn-Seemann (@formbar) June 13, 2019
What other words are related to free charge?
Quiz yourself!
True or False?
Atoms with free charges have electrons that are not tightly bound to the nucleus.
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