🎓 Physics • Magnetism
100% Client-Side Privacy
Coulomb’s Law Calculator
Computes electrostatic force between two charges with Coulomb's constant and electric field intensity.
Coulomb’s Law of Electrostatic Force
Calculate electrostatic attraction or repulsion between point charges: F = k_e · |q₁q₂| / r²
k_e = 8.988 × 10⁹ N·m²/C²
Real-World Electrostatic Presets:
Electrostatic Vector InteractionAttraction (Opposite Sign)
Electrostatic Coulomb Force
35.9502 Newtons (N)
🧲 Attractive Force (Opposite Charges Attract)
Imperial Force8.082e+0 lbf
Electric Field from q₁4.494e+6 N/C
Potential Energy (U)-3.595e+0 J
Step-by-Step Derivation
1. Coulomb’s Law Formula: F = k_e · |q₁ · q₂| / r²
2. Coulomb Constant: k_e = 8.98755 × 10⁹ N·m²/C²
3. Convert to SI Units:
q₁ = 5 uC = 5.0000e-6 C
q₂ = -8 uC = -8.0000e-6 C
r = 10 cm = 1.0000e-1 m
4. Substitution: F = (8.98755 × 10⁹) × |(5.0000e-6) × (-8.0000e-6)| / (1.0000e-1)²
5. Force Magnitude: F = 35.9502 Newtons (N) [8.082e+0 lbf]
6. Interaction Type: Opposite charges attract → Attractive force pulls charges together.
7. Potential Energy: U = k_e(q₁q₂)/r = -3.5950e+0 J (-2.2438e+19 eV)
What is Coulomb’s Law?
Coulomb’s Law quantifies the electric force between two stationary electrically charged particles.
Formula & Step-by-Step Calculation
F = k_e · |q₁ · q₂| / r²
Coulomb constant k_e = 8.98755 × 10⁹ N·m²/C².
Worked Step-by-Step Examples
Example 1
Two 5 μC charges separated by 10 cm
Solution: 22.47 Newtons (Repulsive)
• (8.988e9 × 5e-6 × 5e-6) / 0.10² = 22.47 N
Common Real-World & Academic Use Cases
- ✓ Electrostatic precipitator dust collectors
- ✓ Atomic electron binding forces
- ✓ Laser printing toner transfer
How to Use the Coulomb’s Law Calculator
1
Enter Charges q₁ & q₂
Input microcoulombs μC.
2
Enter Distance
Input centimeters.
3
Review Force
Inspect Newtons and Attractive/Repulsive status.
Frequently Asked Questions
Q: Do like charges attract or repel?
Like charges (positive-positive, negative-negative) repel; opposite charges attract.