The electric force between two charged particles is given by Coulomb's law:
```
F = k * q₁ * q₂ / r²
```
where:
* F is the electric force in newtons (N)
* k is the electrostatic constant (8.988 × 10^9 N m²/C²)
* q₁ and q₂ are the charges of the two particles in coulombs (C)
* r is the distance between the two particles in meters (m)
The electric force between two colloidal particles is inversely proportional to the square of the distance between them. This means that the closer the particles are, the stronger the electric force will be.
The electric force between two charged particles can be attractive or repulsive. If the particles have opposite charges, the force will be attractive. If the particles have the same charge, the force will be repulsive.
The electric force between colloidal particles is one of the factors that determines the stability of a colloidal dispersion. If the electric forces between the particles are strong enough, the particles will be dispersed and will not settle out of solution. If the electric forces are weak, the particles will aggregate and settle out of solution.
The charge on a colloidal particle can be affected by a number of factors, including the pH of the solution, the ionic strength of the solution, and the presence of surfactants. By controlling these factors, it is possible to control the electric forces between colloidal particles and the stability of colloidal dispersions.
