```
F = k * q1 * q2 / r^2
```
Where:
* F is the electric force in newtons (N)
* k is the Coulomb constant (8.988 × 10^9 N m^2/C^2)
* q1 and q2 are the magnitudes of the charges in coulombs (C)
* r is the distance between the charges in meters (m)
If we double the distance between the two charges, the electric force will be reduced by a factor of 4. This is because the electric force is inversely proportional to the square of the distance between the charges.
Therefore:
```
F' = k * q1 * q2 / (2r)^2 = k * q1 * q2 / 4r^2
```
Where F' is the electric force after the distance is doubled.
So:
```
F'/F = (k * q1 * q2 / 4r^2) / (k * q1 * q2 / r^2) = 1/4
```
Therefore, the electric force is reduced by a factor of 4 when the distance between the charges is doubled.
