How to Calculate Coulombs Law
What is Coulombs Law?
Coulomb's Law quantifies the electrostatic force between two charged particles. It states that the force is proportional to the product of the charges and inversely proportional to the square of the distance between them.
Formula
The calculator applies F = k × |q₁ × q₂| / r² where k is Coulomb\'s constant
- F
- k × |q₁ × q₂| / r² where k is Coulomb\'s constant — k × |q₁ × q₂| / r² where k is Coulomb\'s constant
Step-by-Step Guide
- 1Input the magnitudes of two electric charges and the distance between them
- 2The calculator applies F = k × |q₁ × q₂| / r² where k is Coulomb's constant
- 3Results show the electrostatic force in Newtons
Worked Examples
Input
q₁ = 2 μC, q₂ = 3 μC, r = 0.5 m
Result
F ≈ 0.216 N
Using k = 8.99 × 10⁹ N·m²/C²
Common Mistakes to Avoid
- ✕Forgetting to square the distance in the denominator
- ✕Using distance in centimeters instead of meters, which affects calculation accuracy
Frequently Asked Questions
Why does force decrease with distance squared?
The electric field spreads spherically in three-dimensional space, so its strength decreases with the inverse square of distance.
Can this law handle opposite charges?
Yes, opposite charges experience attractive force (negative) while like charges experience repulsive force (positive).
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