Reference Terms
from Wikipedia, the free encyclopedia
Ampere
The ampere (symbol: A) is the SI base unit of electric current equal to one coulomb per second. The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2 times 10–7 newton per metre of length. Electric current is the time rate of change or displacement of electric charge. One ampere represents the rate of 1 coulomb of charge per second. The ampere is defined first (it is a base unit, along with the metre, the second, and the kilogram), without reference to the quantity of charge. The unit of charge, the coulomb, is defined to be the amount of charge displaced by a one ampere current in the time of one second.
Related Stories
1
2
Matter & Energy News
March 18, 2026
Mar. 17, 2026 MIT physicists have built a powerful new microscope that uses terahertz light to uncover hidden quantum motions inside superconductors. By compressing this normally unwieldy light into a tiny region, ...
Mar. 16, 2026 Physicists at UC Santa Barbara have uncovered a new way to manipulate unusual magnetic states by exploiting “frustration” inside a crystal’s atomic structure. The team discovered a rare system where two different kinds of ...
Mar. 16, 2026 Scientists have developed a powerful new computational method that could accelerate the search for next-generation materials capable of turning sunlight into useful chemical energy. The work focuses on polyheptazine imides, a promising class of ...
Mar. 13, 2026 Scientists are exploring a surprisingly simple way to clean up diesel engines: adding tiny droplets of water to the fuel. During combustion, the water rapidly vaporizes, triggering micro-explosions that improve fuel mixing and lower combustion ...
Mar. 10, 2026 Scientists at Oak Ridge National Laboratory have created a new aluminum alloy called RidgeAlloy that can turn contaminated car-body scrap into strong structural vehicle parts. Normally, impurities ...
Mar. 9, 2026 Scientists have found a way to significantly boost “blue energy,” which generates electricity from the mixing of saltwater and freshwater. By coating nanopores with lipid molecules that create a friction-reducing water layer, they enabled ions ...
Mar. 8, 2026 Engineers have discovered an unexpected link between two very different realms of physics: the behavior of electrons in graphene and magnetic waves in specially engineered materials. By designing a thin magnetic film with a hexagonal pattern of ...
Mar. 7, 2026 Solid-state batteries could be safer and more energy-dense than today’s lithium-ion technology, but finding materials that allow ions to move quickly through solid electrolytes has been difficult. ...
Mar. 7, 2026 A team of physicists has experimentally confirmed a long-predicted sequence of exotic magnetic phases in an atomically thin material. When cooled, the material forms tiny magnetic vortices before transitioning into a second ordered magnetic ...
Mar. 4, 2026 A new ultrathin photodetector from Duke University can sense light across the entire electromagnetic spectrum and generate a signal in just 125 picoseconds, making it the fastest pyroelectric detector ever built. The breakthrough could power ...
Mar. 4, 2026 Scientists at the University of Tokyo have captured something never seen before: a frame-by-frame view of how electron spins flip inside an antiferromagnet, a material once thought to be magnetically “invisible.” By firing ultrafast electrical ...
Mar. 3, 2026 Researchers at the University of Basel and the ETH in Zurich have succeeded in changing the polarity of a special ferromagnet using a laser beam. In the future, this method could be used to create adaptable electronic circuits with ...
Latest Headlines
updated 12:56 pm ET
Mar. 16, 2026 Scientists studying a mysterious effect called cosmic birefringence—a subtle twist in the polarization of the universe’s oldest light—have ...
Mar. 14, 2026 Cambridge scientists have discovered a light-powered chemical reaction that lets researchers modify complex drug molecules at the final stages of ...
Mar. 13, 2026 Gold and other heavy elements are born in some of the universe’s most violent events—but scientists still struggle to understand the nuclear steps that create them. Now, nuclear physicists have ...
Mar. 10, 2026 More than a century before quantum mechanics was born, Irish mathematician William Rowan Hamilton stumbled onto an idea that would quietly foreshadow one of the deepest truths in physics. While ...
Mar. 10, 2026 Cosmic voids may seem like the emptiest places in the universe, stripped of matter, radiation, and even dark matter. But they’re far from nothing. Even in these vast empty regions, the fundamental ...
Mar. 9, 2026 Physicists have long struggled to unite quantum mechanics—the theory governing tiny particles—with Einstein’s theory of gravity, which explains the behavior of stars, planets, and the structure ...
Mar. 8, 2026 Physicists have discovered a surprising new “Island of Inversion” in a place no one expected: among nuclei where the number of protons equals the ...
Mar. 7, 2026 Gravity may seem constant, but it actually varies across the planet—and one of the strangest places is Antarctica, where gravity is slightly weaker than expected. Scientists have traced this ...
Mar. 6, 2026 Electrons in solar materials can be launched across molecules almost as fast as nature allows, thanks to tiny atomic vibrations acting like a “molecular catapult.” In experiments lasting just 18 ...
Mar. 3, 2026 An international team combining two major neutrino experiments has uncovered stronger evidence that neutrinos and antimatter don’t behave as perfect mirror images. That subtle difference may hold ...