Electric Field Calculator

The fundamental equation governing a single point charge is derived from Coulomb's law, expressed as E = k × q / r², where E represents the electric field magnitude, k is the Coulomb constant adjusted for the medium's relative permittivity, q is the magnitude of the charge, and r is the radial distance from the charge. For systems containing multiple point charges, the total electric field vector is determined by the principle of superposition, summing the individual electric field contributions from each independent charge in the system.

Consider a point charge with a magnitude of q = 5 µC (5 × 10⁻⁶ C) placed in a vacuum, where relative permittivity is 1. We want to find the electric field strength at a distance of r = 0.5 meters away from the charge. First, determine the electrostatic constant k, which is approximately 8.99 × 10⁹ N·m²/C². Plugging these values into the formula: E = (8.99 × 10⁹) × (5 × 10⁻⁶) / (0.5)². This simplifies to 44,950 / 0.25, resulting in an electric field intensity of 179,800 N/C pointing radially outward.

Always convert your input units into standard International System of Units (SI) measurements before computing—use Coulombs for charge, meters for distance, and Newtons per Coulomb for the resulting field. Pay close attention to the surrounding medium; if the charges are submerged in a dielectric material other than a vacuum or air, make sure to adjust the relative permittivity variable accordingly to maintain calculation accuracy.