# How to Calculate the Repulsion of Two Charges

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Electrical charges show one of the four fundamental forces. Electrical charges will attract and repel each other depending on their charge; equal charges repel, different charges attract. The law to calculate electrical repulsion is called Coulomb's Law, and its equation uses a constant also called the Coulomb's constant. Calculating the Force of Repulsion between electrical charges is the first step to solve problems involving charges, magnetic fields, energy and work.

### Things You'll Need

• Calculator
• Write down your two electrical charges. For example, Q1 = First electrical charge and

Q2 = Second electrical charge.

• Write down the distance between the two charges squared, which is D^2 = Distance between the two charges squared.

• Write down your equation. The Equation is:

Repulsion Force = [ ( Kc ) x ( Q1 ) x ( Q2 ) ] / ( D^2 )

Where:

Kc = Coulomb's constant and the Coulomb Constant is 8.9876 x E^9 in the MKS system.

• Replace your numbers in the equation and solve with the calculator.

For example:

Q1 = 9 x E^-4

Q2 = 12 x E^-5

D = 1, D^2 = 1

Repulsion Force = [ ( 8.9876 x E^9 ) x ( 9 x E^-5 ) x ( 12 x E^-5 ) ] / ( 1 )

After solving operations in the calculator:

Repulsion Force = 97.066 Newtons

## Tips & Warnings

• One of the conclusions from Coulomb's Law is that the magnitude of the repulsion force is equal to the magnitude of the attraction force.

## References

• Photo Credit Jupiterimages/Photos.com/Getty Images
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