Question

What is the equation for calculating the electrical force, Fe, between two charges?

Answer 1

Answer:

$F_e = \frac{1}{4 \pi \epsilon_0} \frac{q_1 q_2}{r^2}$

Explanation:

The electrostatic force (also called Couloumb force) between two electrical charge is given by the following formula:

$F_e = \frac{1}{4 \pi \epsilon_0} \frac{q_1 q_2}{r^2}$

where:

$\epsilon_0=8.85\cdot 10^{-12} Fm^{-1}$ is the vacuum permittivity

$q_1$ is the magnitude of the first charge

$q_2$ is the magnitude of the second charge

$r$ is the distance between the two charges

This formula gives only the magnitude of the force. The direction depends on the relative sign of the two charges:

- If the two charges have same sign, the force is repulsive (this corresponds to a positive sign in the formula)

- If the two charges have opposite sign, the force is attractive (this corresponds to a negative sign in the formula)

Answer 2

Fe=k|q1q2| / r^2

(k is the electrostatic constant which has a value of 8.99x10^9 Nm^2/c^2, r is the distance between the charges and q is the quantity of the charges.)