In physics, we know that objects with mass attract each other through gravitational force. Similarly, charged particles exert an electrostatic force on one another. Coulomb's Law allows us to calculate the magnitude and determine the direction of this force between two point charges.

What is Coulomb's Law?

In simple terms, Coulomb's Law describes the force and its direction between two stationary, electrically charged particles.

Definition

Coulomb's Law states that the electrostatic force between two point charges is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them. The force acts along the straight line connecting the two charges.

Formula

The mathematical formula for Coulomb's Law is:

$$F=k \frac{|q_1 q_2|}{r^2}$$

Units

In the International System of Units (SI), each term in Coulomb's Law has the following units:

  • Force (F):Newtons (N)
  • Coulomb's constant (k):Newton-square meters per Coulomb-squared (N·m²/C²)
  • Charge (q₁ and q₂):Coulombs (C)
  • Distance (r):Meters (m)

How to Use This Coulomb's Law Calculator

Follow these simple steps to use the calculator:

  1. Enter the value for the first charge (q₁) in its input box and select the appropriate unit from the dropdown menu.
  2. Enter the value for the second charge (q₂) in its input box and select its unit.
  3. Enter the distance between the two charges and select the distance unit.
  4. The Coulomb's constant (k) is pre-filled with the standard value in a vacuum.
  5. The calculated electrostatic force is instantly shown in the "Resultant Force" box.
  6. You can change the unit of the resultant force from its dropdown menu, and the result will automatically update.
  7. For a new calculation, click the "Clear" button to reset all fields.
Author Image

About the Author

Mr. Singh

Mr. Singh is a passionate educator and skilled writer who brings science to life. With a Master's in Physics and years of teaching, he combines 5+ years of coding and content creation expertise to make complex ideas engaging for everyone.