Two identical charges, 2.0m apart, exert forces of magnitude 4.0N on each other. The value of either charge is : (ke = 9*10^9 N. M^2. C^-2)

4.216 * 10^ (-5) C

Explanation:

Parameters given:

Electrostatic force between charges, F = 4N

Distance between the charges, r = 2 m

The electrostatic force acting between two charged particles, q1 and q2, separated by a distance, r, is given as:

F = (k * q1 * q2) / r²

Where k = Coulombs constant.

Since q1 = q2 = q,

F = (k * q²) / r²

Inputting all the values:

4 = (9 * 10^9 * q²) / 2²

=> 16 = (9 * 10^9 * q²)

=> q² = 16 / (9 * 10^9)

q² = 1.78 * 10^ (-9)

=> q = 4.216 * 10^ (-5) C

The value of both charges is 4.216 * 10^ (-5) C.