A particle with a charge of $-3\mathrm{.}8nC$ starts from rest and passes through a potential difference of $8\mathrm{.}5{10}^{8}V.$ It has a mass of $1\mathrm{.}0g.$

a$.$ Calculate its velocity after passing through the potential difference.

b$.$ If the potential difference arises parallel charged plates, toward which plate does the charged particle move $($the positive or the negative plate$)?$

c$.$ Calculate the work done on this particle by the electric force.