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The ampere is named for French physicist and mathematician André-Marie Ampère (1775–1836), who studied electromagnetism and laid the foundation of electrodynamics.In recognition of Ampère's contributions to the creation of modern electrical science, an international convention, signed at the 1881 International Exposition of Electricity, established the ampere as a standard unit of ...
For example, the joule per kelvin (symbol J/K) is the coherent SI unit for two distinct quantities: heat capacity and entropy; another example is the ampere, which is the coherent SI unit for both electric current and magnetomotive force. This illustrates why it is important not to use the unit alone to specify the quantity.
Factor () Value Item 10 −19: 160 zA Current flow of one electron per second : 10 −12: 1-15 pA Range of currents associated with single ion channels [calcium (1 pA), sodium (10-14 pA), potassium (6 pA)] as measured by patch-clamp studies of biological membranes
For example, in a copper wire of cross-section 0.5 mm 2, carrying a current of 5 A, the drift velocity of the electrons is on the order of a millimetre per second. To take a different example, in the near-vacuum inside a cathode-ray tube, the electrons travel in near-straight lines at about a tenth of the speed of light.
The electromagnetic force is responsible for many of the chemical and physical phenomena observed in daily life. The electrostatic attraction between atomic nuclei and their electrons holds atoms together. Electric forces also allow different atoms to combine into molecules, including the macromolecules such as proteins that form the basis of life.
In the 19th and early 20th centuries, electricity was not part of the everyday life of many people, even in the industrialised Western world. The popular culture of the time accordingly often depicted it as a mysterious, quasi-magical force that can slay the living, revive the dead or otherwise bend the laws of nature.
Ahead, we’ve rounded up 50 holy grail hyperbole examples — some are as sweet as sugar, and some will make you laugh out loud. 50 common hyperbole examples I’m so hungry, I could eat a horse.
For example, a 12-inch-long coil (ℓ = 12 in) with a long plunger with a cross section of one inch square (A = 1 in 2) and 11,200 ampere-turns (N I = 11,200 Aturn) had a maximum pull of 8.75 pounds (corresponding to C = 0.0094 psi). [10] The maximum pull is increased when a magnetic stop is inserted into the solenoid.