Electric Field Calculator

The field is computed as k·|Q|/r² using the absolute value of the source charge, since field strength (a magnitude) is always reported as a positive number regardless of the charge's sign — direction is handled separately by the 'direction' flag. Potential, by contrast, is computed as k·Q/r using the charge's actual signed value, so a negative source charge produces a negative potential, reflecting that a negative charge pulls a positive test charge in and does positive work on it as it approaches.

It's simply the calculated electric field divided by 4, illustrating the inverse-square relationship E = k|Q|/r² directly: doubling r multiplies r² by 4, so the field always drops to exactly one quarter of its original value at twice the distance, independent of how large the charge is. It's a fixed ratio, not a separate calculation from a different charge or distance.

A coulomb is an enormous unit of charge — Coulomb's constant k is about 8.98755×10⁹ N·m²/C², so even modest, realistic static or circuit charges are typically measured in microcoulombs (1 μC = 1×10⁻⁶ C) or nanocoulombs (1 nC = 1×10⁻⁹ C). Entering a whole number like 1 or 10 coulombs directly would represent an unrealistically massive charge and produce field and force values far beyond anything encountered outside of specialized high-energy contexts.

No — it's a simple +1 or −1 label, not a vector: +1 means the field points away from the source (a positive charge repelling), and −1 means it points toward the source (a negative charge attracting). It doesn't account for the test charge's own sign or give you a spatial direction; you have to reason separately about whether the test charge is attracted or repelled based on both charges' signs.