F = 1440 N. The repulsion force between two identical charges, each -8.00x10⁻⁵C separated by a distance of 20.0 cm is 1440 N.
The easiest way to solve this problem is using Coulomb's Law given by the equation
, where k is the constant of proportionality or Coulomb's constant, q₁ and q₂ are the charges magnitude, and r is the distance between them.
We have to identical charges of -8.00x10⁻⁵C, are separated by a distance of 20.0 cm, and we need to know the force of repulsion between the charges.
First, we have to convert 20.0 cm to meters.
(20.0 cm x 1m)/100cm = 0.20 m
Using the Coulomb's Law equation:

