Coulomb's Law Calculator

Coulomb's law gives the force between two point charges.

How the Math Works

Coulomb's Law calculates the electric force between two charged particles using the formula F = k·q₁·q₂ ÷ r², where k is Coulomb's constant (8.99×10⁹ N·m²/C²). The force depends directly on the product of the charges (q₁ and q₂) and inversely on the square of their separation distance (r). A larger charge or closer proximity increases the force magnitude, while opposite charges attract and like charges repel. This mathematical relationship quantifies the fundamental electrostatic interaction governing charged particles at a distance.

Practical Applications

This calculation is essential in electrical engineering for designing circuits, capacitors, and electronic components where charge interactions determine performance. Physicists use it to model atomic and molecular behavior, analyze particle accelerators, and study plasma dynamics. In medical imaging like MRI machines, understanding electric forces helps optimize electromagnetic field configurations. Engineers also apply it to assess electrostatic discharge risks in sensitive electronics, ensuring safety and reliability in real-world systems.

Day-to-Day Use

Coulomb's Law underpins technologies we use daily, from smartphones and touchscreens to electric vehicles and home appliances. It explains how static shocks occur when touching doorknobs and guides the design of efficient batteries and solar panels. Even in everyday items like photocopiers and laser printers, electric forces manipulate toner particles. By quantifying these invisible forces, the law ensures safer electrical systems and enables innovations in renewable energy and wireless communication technologies that shape modern life.

Worked example

5 µC & 5 µC at 0.1 m → 22.5 N.

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