# How to Calculate Magnitude of Electrostatic Force using Coulomb's Law - Tutorial

## How to Calculate Magnitude of Electrostatic Force using Coulomb's Law - Definition, Formula and Example

##### Definition:

Coulomb's law of Force is the basic law of electrostatic which states that the force between two charged particles which consists of magnitude force is directly proportional to the product of their charges or inversely proportional to the square of the distance between them.

##### Formula :
F = K*(Q1*Q2)/r2
K = 1 / ( 4πε0)
###### Where,

K = Coulomb constant Q1 & Q2 = Points charge r = Distance F = Electrostatic Force ε0 = Permittivity of empty space. 8.85419*10-12 c2/N.m2

##### Example :

A point charge of 3.00*10-6 C is 12.0cm distant from a second point charge of -1.50*10-6 C. Calculate the magnitude of the electrostatic force on each charge.

##### Given,

Q1 = 3.00*10-6 C Q2 = -1.50*10-6 C r = 12 cm = 0.12 m

##### To Find,

Magnitude of Electrostatic Force (F)

##### Solution:

Let us substitute the given values in above formula, F = ( (3.00*10-6) * (1.50*10-6) ) / ( (4 * 3.14) * (8.85419*10-12) * (0.12)2 ) F = ( (0.000003) * (0.00000105) ) / ( (12.56) * (0.00000000000885419) * (0.0144) ) F = ( 4.5*10-12 ) / ( 1.6014042*10-12 ) F = 2.8100338e-24 F = 2.8100 N