Why a coulomb has 6.24 × 10^18 electrons ?

[my_books]

Why a coulomb has 6.24 × 10^18 electrons and How it is Caculated ?

 

[ahmed osama]

Why a coulomb has 6.24 × 10^18 electrons and How it is Caculated ?

sorry can i add another ques. to that !!

this mean that the current should be quantized by qunata = 6.24 × 10^18 electrons since current = charge / sec. which mean col. / sec. !!!!!!!!!!!!

 

[Old Nick]

It's is an SI unit of measurement, nothing magical about it.

Somebody at some time decided that the unit of charge would be the amount of charge transported by 1 amp in 1 second, and then named it the Coulomb.
Note the capital C in Coulomb!!!

The reason is the same as why a centimeter is 10 millimeters.
Or an hour has 60 seconds.

 

[FvM]

The elementary charge (an electron is just one of more charged elementary particles) can be (more or less simply) measured with physical experiments, that involve free charged particles.

 

[z_ghadiani]

In addition to last answers which are very good specially Old Nick, there can be another reason that Columb has not been given up, That's becuse despite electron Columb is a large unit which can be used more easily in everyday applications.

 

[my_books]

How the number of electrons in a columb was counted ?

 

[javar]

This number was not counted.
To measure the amount of electrons in this unit are the result of the experiment used by Robert Millikan and the definition of coulomb in the international system of units, this definition is as follows:

A Coulomb (C) is the amount of electric charge passing through the cross section of a driver in a second, when the driver circulates an Amper.

The experiment allowed Millikan find the burden of the electron in units coulomb and therefore is able to estimate the number of electrons in a coulomb.

The issue now moves to the definition of an Amper in SI; this is defined as:

Ampere is the intensity of a steady flow maintained that two drivers in parallel, straight, long endless, circular section despicable and located at a distance of one meter of each other in a vacuum, would produce a force equal to 2 • 10 Λ- 7 newton per metre. Its symbol is A.

Regards

 

[yousefsam]

Why a coulomb has 6.24 × 10^18 electrons ?

The charge of electron is constant and equal to (1q=1.6021910×10^-19 C), so to find the coulomb we must divide on the charge of electron so
(1C=1q/(1.6021910×10^-19)) and this equal to (1C=6.24145311^18 q).