Question

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

Answer 1

The third choice:
`2.81*10^(16) \: \text{protons}`

Step-by-step 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 = (+4.5mC)/(+1.6*10^(-19)C) = (+4.5*10^(-3)C)/(+1.6*10^(-19)C)`

`\boxed{n =2.81*10^(16) \: \text{protons}}`

which is the 3rd choice.