Hi!
I just read that 1 ampere is about 6.3 x 10^18 electrons passing through a point in a second.
Number is large, but where does it come from?
I mean, how did someone calculate this number?
An ampere is defined as one coulomb per second, so it is determined by the charge on the electron. This was first measured by Millikan and Fletcher in 1909. The currently accepted value is 1.602 x 10^-19 C ; therefore, there are 6.242 x 10^18 electrons per Coulomb.