Re:2019 redefinition of the SI base units
by Aardwolf on Monday July 01, 2019 @04:49PM
(#20329592)
Why is ampere a base unit instead of charge? Charge seems the more fundamental one to me, like mass is, and ampere feels more derived, as if volumetric flow rate were made a base unit instead of mass.
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Because the standards are made for people who makes measurement devices. It is much easier to measure electric current than charge.
They also did make charge more fundamental, as they derive the Ampere by fixing the charge of an electron.
None of them are really fundamental. Some people feel that force is more fundamental than mass since force seems to be a "real" thing that happens while mass is just an abstract quantity that helps us predict forces. It's all human psychology, practical issues with measurement, and legacy. Quite a few of the base units are entirely redundant (candela, kelvin, mole) but we have them because of our human weaknesses.
Re:2019 redefinition of the SI base units
by anticensor on Monday July 01, 2019 @05:09PM
(#20329785)
You cannot change the basic dimensionalities after the fact. Electric current was chosen at the time, rather than charge, hence it has been defined in terms of electron's charge.
Think of Charge as a collection of Amperage across a period of Time, or a supply of Charge that can yield a particular Amperage of current for a sustained amount of Time.
https://electronics.stackexchange.com/questions/23449/why-is...