constant

electron charge

The fundamental unit of electric charge carried by a single electron.
24 related articles

Description

The electron charge is the fundamental unit of electric charge, denoted by the symbol e, and is the amount of negative charge carried by a single electron. It is one of the most precisely measured constants in physics, with a value of approximately 1.602 × 10⁻¹⁹ coulombs. This quantity is not just a property of electrons; it is the basic quantum of charge in nature, meaning that all free electric charges are integer multiples of e, a fact known as charge quantization.

History

The electron charge was first measured by Robert Millikan in his famous oil-drop experiment in 1909, which earned him the Nobel Prize in Physics in 1923. Millikan's careful measurements showed that the charge on oil droplets was always a multiple of a single value, providing direct evidence for charge quantization.

How it works

The electron charge is a fundamental property of the electron, a point-like particle in the Standard Model. It determines the strength of the electromagnetic interaction between electrons and other charged particles, such as protons and photons. The value of e is so fundamental that it appears in countless equations, from the fine-structure constant that characterizes atomic spectra to the Coulomb force law that governs electric interactions.

In practice

The electron charge is essential in electronics, where it determines the current in circuits (as the charge per electron times the number of electrons flowing per second), and in electrochemistry, where it relates to the Faraday constant used in electrolysis and battery design.

Fun fact

The electron charge is so small that a typical lightning bolt carries about 10²⁰ electrons, which is more than the number of stars in the observable universe.

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Related articles · 24

The Moon's Electric Skeleton: How Charge Hides in Eternal Shadow
In the Moon's polar craters, where sunlight never reaches, regolith may accumulate electric charge for decades, buried deep below the surface. It's like a bank account where deposits and balance don't match: a particle delivers energy, but the charge doesn't always stay put.
Chemical Physics2026-08-192 minarXiv:2608.18623express
Quantum Chemistry for Hundreds of Thousands of Atoms
Water in a glass looks continuous, but it's actually a dance of trillions of molecules constantly breaking and forming bonds. Seeing this dance in full detail was previously impossible: accurate calculations that account for the quantum properties of electrons could only handle tiny droplets of a few hundred atoms. The new model UBio-MolFM changes the game.
Instrumentation2026-08-181 minarXiv:2608.17842express
Counting to One: How a Camera Catches Light One Particle at a Time
Catching light one particle at a time is like hearing a whisper in a roaring factory. An electron-multiplying camera (EMCCD) can do exactly that: it turns a single photon hitting a pixel into an avalanche of electrons that can be measured. These cameras are mounted on telescopes to spot a barely visible planet next to a dazzling star.
HEP Experiment2026-08-151 minarXiv:2608.15367express
How Charge Flows from Z-Boson Decays
In 1994–1995, the LEP accelerator collided electrons and positrons, producing Z bosons that promptly decayed into showers of particles. The DELPHI detector recorded these events, and now, decades later, a new pattern has been found in that data: the electric charge within particle jets is not distributed randomly but follows a simple sine curve.
Quantum Physics2026-08-012 minarXiv:2608.00468express
Where Charge Lives
Electric charge is a slippery thing. You can measure how much there is in the entire universe or in a single particle, but try to point your finger and say, 'Right here, in this cubic centimeter, there is exactly this much charge right now,' and you hit a fundamental wall. The issue is that total charge, which physicists denote by the letter Q, is nonlocal.
Statistical Mech2026-07-281 minarXiv:2607.25625express
How symmetry hides in a spin chain
A quantum chain is like a string of lights, where the bulbs are the spins of particles. Ideally, all bulbs glow in sync, following a common rhythm: that's symmetry. But if you cut off a piece of the string, the rhythm can get out of step: within that segment, symmetry is broken. Physicists study a chain of strongly interacting particles (the XYZ model).
Cosmology2026-07-272 minarXiv:2607.24742express
Weighing Neutrinos: How Much Does a Ghost Particle Weigh?
In 1998, physicists caught neutrinos doing something astonishing: the particle changes its type on the fly. That is only possible if it has mass. This became the only laboratory proof of physics beyond the Standard Model. But exactly how much a neutrino weighs remains a mystery.
HEP Theory2026-07-242 minarXiv:2607.22938express
How Mass and Charge Swap Roles in a Multidimensional World
A carousel doesn't just spin you around in a circle — with each revolution, it also slightly screws itself into the ground. This corkscrew-like motion is the essence of the NUT charge, a special property of spacetime that physicists have been studying since the mid-20th century.
Quantum Physics2026-06-172 minarXiv:2606.19585express
Noise in the Trap: Dust Grains vs. Quantum
A quantum computer is like an orchestra where each ion is a musician and laser pulses are the conductor's baton. But if someone in the audience rustles, the delicate melody of quantum states goes off key.
The Silent String of Gravity: Hunting for κ
The weak equivalence principle, silently tested since the time of Galileo and laid at the foundation of general relativity, states: all bodies fall equally, regardless of their internal composition.
Quantum Physics2026-05-032 minarXiv:2605.08148express
Echo of the Void: How to Catch the Invisible
A palm hovering over a hot stove feels the heat even when the surrounding air seems cool. Something similar happens to electrons in the Aharonov–Bohm effect: the particle senses an electric voltage even though it enters a region where the field has already been switched off.
Nuclear Theory2026-05-021 minarXiv:2605.01573express
Why the Periodic Table Ends with Lead
The atomic nucleus is not a solid ball but a dense swarm of tiny particles called quarks, glued together by a special glue (the strong force). In light nuclei, such as calcium, this swarm is simply arranged: the numbers of the two quark types, up and down, are almost equal, like the white and black keys in an octave.
HEP Experiment2026-04-291 minarXiv:2604.26784express
Rare decay spotted for the first time
A coin landing on its edge is about as rare as a heavy B meson decaying into a light pion and an electron-positron pair. Over a decade of collider operation, only a handful of such events have accumulated, but physicists have finally managed to spot them. The decay probability is about 2.4×10⁻⁸.
Nuclear Experiment2026-04-271 minarXiv:2604.24220express
Stretching a Deuterium Nucleus with Light
A drop of water stretches in a strong electric field. The deuterium nucleus, a bound pair of a proton and a neutron, behaves the same way, except here the field comes from a passing gamma ray, and instead of just stretching, the nucleus can simply fall apart.
HEP Lattice2026-04-141 minarXiv:2604.13269express
Kaon Under the Lens: How a Particle Responds to Light
If you place a kaon in an electric field, it stretches slightly, like a balloon rubbed on wool. This response, the electric polarizability, shows how rigidly the particle is built inside. For the charged kaon, it has been measured for the first time, and the number is about one ten-thousandth of the volume occupied by a proton.
Nuclear Experiment2026-04-032 minarXiv:2604.02825express
Electric Charge Transfer in Nuclear Collisions: A New Technique
When heavy nuclei collide in accelerators, a multitude of particles is produced, and physicists want to understand how electric charge moves through this chaos. Two trains crash into each other: the passengers (quarks) scatter, but their luggage (charge) may end up far from the crash site.
Nuclear Experiment2026-02-242 minarXiv:2602.20828express
The Deuteron's Electric Dipole Moment: Hunting for Asymmetry
The nucleus of deuterium, or the deuteron, can be pictured as a microscopic spinning top. If its charge distribution is not perfectly symmetric, then in an external electric field this top experiences a minuscule tilt of its spin axis.
Atomic Physics2026-02-162 minarXiv:2602.14980express
Hydrogen Atom Measured to Trillionths
The hydrogen atom is like a tiny clock, ticking with a precision engineers can only dream of. When an electron jumps between orbits, it absorbs or emits light at a strictly defined frequency: that's the 'tick.' In the new work, physicists caught one such transition, between the 2S and 6P states, and measured its frequency with an…
Applied Physics2026-02-081 minarXiv:2602.08056express
Glass That Remembers Touch
A flexible screen as thin as a human hair is glass you can bend. But this marvel has a quirk: touch it, and an invisible electric charge lingers on the surface. Like dust on polished furniture, it builds up and interferes with operation.
HEP Experiment2026-01-271 minarXiv:2601.19185express
Neutron in the Light
The neutron is a particle with no charge but with internal structure. Like a ball that looks smooth on the outside but has a complex filling inside. Scientists have long wanted to understand how electric and magnetic forces are distributed inside the neutron. To do this, you need to "feel" it — collide it with its antiparticle and see what happens.
General Relativity2026-01-221 minarXiv:2601.16325express
Gravity and Charge: Physics' Blind Spot
Since the days of Galileo, it was believed that in a vacuum all bodies fall identically. Einstein elevated this to a principle: gravity travels at the speed of light and is the curvature of spacetime.
HEP Lattice2026-01-101 minarXiv:2601.06582express
Peering Inside the Proton with an Electron Beam
An electron beam strikes a proton like a billiard ball hitting another ball. But between them is no empty space: the particles exchange virtual photons and Z bosons, like players passing a ball behind their backs. This exchange slightly alters the scattering trajectory, and hidden within it is a hint of new physics.
cs.CE2026-01-011 minarXiv:2601.00505express
How a Drug's Charge Alters Its Path Under the Skin
After an injection under the skin, a drug doesn't just spread out like ink in water. Antibody molecules carry an electric charge, and that charge makes them interact with surrounding tissues — much like a magnet attracts or repels iron filings.
Nuclear Experiment2025-10-161 minarXiv:2510.21768express
Tantalum Nucleus Reveals Electric Asymmetry
Measured dipole moment of tantalum-181: 3.39 × 10⁻³² e·cm — like spotting a one-atom shift across the entire Solar System. An ordinary atomic nucleus is perfectly balanced, like a spinning top. In tantalum, that balance is broken: the positive and negative charges are slightly offset from each other.