What does faraday mean?
The faraday is a unit of electric quantity used almost exclusively in electrochemistry. It represents the total electric charge carried by one mole of electrons — approximately 96,485 coulombs, a value closely related to the Faraday constant. In practical terms, one faraday is the amount of charge needed to deposit or dissolve one mole of a singly charged substance at an electrode, which makes it a convenient yardstick in electrolysis calculations: plating out a mole of copper, for instance, requires two faradays because the copper ion carries a double charge. The unit honours Michael Faraday (1791–1867), the English scientist whose experiments established the quantitative laws of electrolysis on which the concept rests. Although the International System of Units favours the coulomb, the faraday survives in chemistry courses and older technical writing as a compact way to link electrical measurement with the mole, the chemist's standard counting unit for matter.
nounA faraday is a unit of electric quantity equal to the charge of one mole of electrons, approximately 96,485 coulombs, used chiefly in electrochemistry.
- A unit of electric charge equal to the charge carried by one mole of electrons, approximately 96,485 coulombs, used in electrochemical calculations.
"Depositing one mole of silver from a silver nitrate solution requires exactly one faraday of charge."
"Electrolysing a mole of aluminium ions requires three faradays of electricity."
"The students converted the measured current into faradays to determine how much copper had been deposited."
Standard plural form, used when expressing quantities of charge greater than one faraday.
"Refining a tonne of copper requires many thousands of faradays of electrical charge."
The faraday isn't named for the unit itself but honours Michael Faraday, the bookbinder's apprentice who became the father of electrochemistry.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of faraday
The faraday is an eponymous unit coined in honour of Michael Faraday, the pioneering nineteenth-century English experimentalist whose laws of electrolyysis quantified the relationship between electric charge and chemical change. The term entered scientific vocabulary in the late nineteenth or early twentieth century, when electrochemists sought a practical charge unit tied directly to the mole concept. Because it derives from a personal surname rather than an ancient root, it has no classical cognates, though it shares its namesake with the farad, the unit of capacitance.
How faraday is actually used
The faraday is a legacy unit found mainly in electrochemistry textbooks and older literature; modern scientific work uses the coulomb instead. The word is also written capitalized (Faraday) in some sources, reflecting its origin as an eponym.
Easily confused with faraday
The farad is the SI unit of electrical capacitance, whereas the faraday is a much larger non-SI unit of electric charge equal to about 96,485 coulombs.