Charge It! Charges and Magnets#
Example 3: Electrons in a Coulomb?#
The Question:
Okay. So a Coulomb creates a lot of force. Just how much electricity is there in an electron? Or a proton? That is, what is the charge of an electron in Coulombs and how many electrons are there in a single Coulomb?
The Answer:
The elementary unit of charge is the magnitude of the charge of an electron which is identical to that of a proton…they only differ by their sign. A proton is positive and an electron is negative. That elementary unit is called \(e\) and we’ll make considerable use of it later. For now,
\[
e=1.6 \times 10^{-19} \text{ C} \nonumber
\]
Not very much. So now the number of electrons?
\[\begin{split}
\begin{align*}
\text{number of electrons in 1 C}&=\frac{1 \text{ electron}}{1.6 \times 10^{-19}
\text{ C}}=6.25 \times 10^{18} \text {electrons} \nonumber \\
&= 6,250,000,000,000,000,000 \nonumber \end{align*}
\end{split}\]
which is rather a lot.