The Electric Force is the interaction between two charged objects. Like gravity, it acts over a distance, but it is significantly stronger and can both attract and repel.

Coulomb’s Law

The magnitude of the force between two point charges is given by:

\[F_e = k \frac{|q_1 q_2|}{r^2}\]
  • $k$: Coulomb’s Constant ($\approx 8.99 \times 10^9 \text{ N}\cdot\text{m}^2/\text{C}^2$)
  • $q_1, q_2$: Magnitudes of the charges (Coulombs)
  • $r$: Distance between the centers of the charges (meters)

The Inverse Square Law

Because $r^2$ is in the denominator, if you double the distance between two charges, the force becomes one-fourth as strong.

💡 Quick Concept Check:

If the distance between two charges is tripled, what happens to the force between them?

Click to Reveal Answer
The force is reduced to **one-ninth** of its original value ($1/3^2 = 1/9$).
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