Answer:
The third choice: [tex]2.81*10^{16} \: \text{protons}[/tex]
Explanation:
The cork is positively charged, therefore we know tat there must be excess of positively charged protons present.
The charge [tex]p^+[/tex] of a proton is
[tex]p^+ = +1.6*10^{-19}C[/tex];
therefore, the number [tex]n[/tex] that makes up a charge of [tex]+4.5mC[/tex] is
[tex]n = \dfrac{+4.5mC}{+1.6*10^{-19}C} = \dfrac{+4.5*10^{-3}C}{+1.6*10^{-19}C}[/tex]
[tex]\boxed{n =2.81*10^{16} \: \text{protons}}[/tex]
which is the 3rd choice.
