Here's the formula:

F = k * (q1 * q2) / r²

Where:

* F is the force between the two charges (in Newtons, N)

* k is Coulomb's constant, approximately 8.98755 × 10⁹ N⋅m²/C²

* q1 and q2 are the magnitudes of the two charges (in Coulombs, C)

* r is the distance between the centers of the two charges (in meters, m)

Important Notes:

* Direction: The force is attractive if the charges have opposite signs (one positive and one negative), and repulsive if they have the same sign (both positive or both negative).

* Vector quantity: Force is a vector, meaning it has both magnitude and direction. The direction of the force is along the line connecting the two charges.

* Inverse square law: The force is inversely proportional to the square of the distance between the charges. This means that if you double the distance between the charges, the force will be reduced to one-fourth of its original value.

Example:

Let's say you have two charges:

* q1 = +2.0 μC (micro Coulombs)

* q2 = -3.0 μC

* The distance between them is r = 0.5 m

First, convert the charges to Coulombs:

* q1 = 2.0 × 10⁻⁶ C

* q2 = -3.0 × 10⁻⁶ C

Now, plug the values into Coulomb's Law:

F = (8.98755 × 10⁹ N⋅m²/C²) * (2.0 × 10⁻⁶ C * -3.0 × 10⁻⁶ C) / (0.5 m)²

F ≈ -0.216 N

The negative sign indicates that the force is attractive.

In summary, Coulomb's Law provides a simple and fundamental way to calculate the force between two charges. This law is crucial in understanding many phenomena related to electricity and magnetism.