Question

A small cork is charged to +4.50 mC. Find the number of excess elementary charges (protons or electrons)

Answer 1

Answer:

The third choice: $2.81*10^{16} \: \text{protons}$

Explanation:

The cork is positively charged, therefore we know tat there must be excess of positively charged protons present.

The charge $p^+$ of a proton is

$p^+ = +1.6*10^{-19}C$;

therefore, the number $n$ that makes up a charge of $+4.5mC$ is

$n = \dfrac{+4.5mC}{+1.6*10^{-19}C} = \dfrac{+4.5*10^{-3}C}{+1.6*10^{-19}C}$

$\boxed{n =2.81*10^{16} \: \text{protons}}$

which is the 3rd choice.