Question

Two plates labeled A and B are separated and initially neutral. Through some mechanism, 7 μC (microcoulombs) of positive Charge are move from plate A to plate B. Answer below questions about the final electrostatic state of each plate after the transfer. 1) After the transfer is complete, indicate how many excess protons (or singly positive ions) are on Plate B ? 2) After the transfer is complete, what is the sign and number of the uncanceled elemental charges on Plate A. Note: positive values require no sign.

Answer 1

1) Approximately
`4\,\,\,10^(13)` excess protons

2) negative
`4\,\,\,10^(13)` (
`-4\,\,\,10^(13)`)

Step-by-step explanation:

1)

Recall that the charge of an electron or proton is approximately:
`1.6\,\,\,10^(-19) \,C`

Therefore, to find the number of protons transferred in 7 micro-Coulombs of charge, we do:

`(7\,\,10^(-6)\,)/(1.6\,\,10^(-19)) \approx 4\,\,10^(13)`

Approximately
`4\,\,\,10^(13)` excess protons

2)

The sign and number of uncanceled elemental charges on plate A is therefore negative
`4\,\,\,10^(13)` , because the same number of positive charges were removed from it, changing its neutrality