A charged capacitor consists of two large flat plates, one with positive charge +Q and the other negative charge -Q. An external agent trans an electron from the positive plate to the negative and also transfers a proton from the negative plate to the positive plate. There is a constant voltage difference delta V between the plates and the transfer of a a single electron or proton does not alter that voltage.
Consider the following statements:
i.) the work done by the agent to move the electron is positive
ii.) the work done by the agent to move the proton is positive
iii.) the magnitude of the work to transfer the proton is the same as the magnitude of the work to transfer the electron.
iv.) the magnitude of the work done to transfer the electron is less than the magnitude of the work to transfer the proton.
Which of the statements are true? (MC)
c.) only iii
d.) ii and iv
e.) i, ii, and iii
The Attempt at a Solution
I understand that i and ii are correct because they are both moving in the same direction as the force that's being applied (the external force). I don't understand is why the answer is E--because I don't understand why the forces are the same (making the works the same magnitude). If the masses of the proton and electron are different, wouldn't that make the forces different?