Coulomb's Law Calculator
Calculate the electrostatic force between two point charges using Coulomb’s law.
Electrostatic Force (F)
Interaction
Calculation Details
Understanding Coulomb's Law
Coulomb's law describes the electrostatic force between two stationary, electrically charged particles. It states that the magnitude of the 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. This relationship, expressed as F = k·|q₁·q₂|/r², is one of the foundational equations of electromagnetism.
The Coulomb Constant
The Coulomb constant k equals approximately 8.9875 × 10⁹ N·m²/C². It is also written as k = 1/(4πε₀), where ε₀ is the permittivity of free space.
Attractive vs. Repulsive Forces
- Like charges repel: Two positive or two negative charges push each other apart.
- Opposite charges attract: A positive and a negative charge are drawn toward each other.
- Inverse-square law: Doubling the distance reduces the force to one quarter of its original value.
Key Formulas
- F = k·|q₁·q₂|/r² — Electrostatic force magnitude
- k = 8.9875 × 10⁹ N·m²/C² — Coulomb constant
- k = 1/(4πε₀) — Coulomb constant from permittivity
References
The formula and physical constant used in this calculator are based on established physics principles and verified sources:
Related Calculators
Note: This calculator assumes ideal point charges in a vacuum and does not account for the dielectric properties of surrounding media, charge distribution, or quantum effects. Results are based on classical electrostatics and may differ from real-world scenarios.