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← Electric Charges, Fields, and Gauss's Law
8.1

Electric Charge and Electric Force

Electric charge is a fundamental property of matter, and Coulomb's law quantifies the force between point charges.

Change15–25% of exam
All TopicsNext8.2Conservation of Electric Charge and the Process of Charging
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Context

What this topic is and why it exists

Imagine two magnets snapping together across a table — now multiply that invisible reach across the entire universe.
That's electric force, and it governs everything from lightning strikes to the atoms holding your hand together.
Here's the foundation: all matter carries a property called charge.
It comes in two flavors — positive and negative — and the smallest chunk of it you'll ever find in nature is the elementary charge *e*, carried by a single proton (+e) or electron (−e).
Neutrons sit this dance out entirely.
Charge isn't a vector; it's just a number with a sign, a scalar that tells you how strongly something participates in the electric game.
Now, Coulomb's law is where the physics gets powerful.
Take two charged objects, shrink them down to points (because their size doesn't matter at large enough distances), and the force between them equals the product of their charges divided by the square of the distance separating them, all scaled by a constant: |Fₑ| = (1/4πε₀)(|q1q_{1}q1​q2q_{2}q2​|/r2).r^{2}).r2).
Double the distance?
The force drops to a quarter.
Double one charge?
The force doubles.
That elegant inverse-square relationship mirrors gravity — except electric force can attract *or* repel, making it far richer and, frankly, far more interesting.
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