A metal sphere is insulated electrically and is given a charge. If 50 electrons are added to the sphere in giving a charge, how many Coulombs are added to the sphere?

Answer 1

This question essentially comes down to how many Coulombs of charge 50 electrons have (i.e., the sphere, the initial charge, etc., are irrelevant). So, knowing that one elementary charge is

e = 1.6×10^-19 C

and that 50 electrons will have a total charge of -50e,

-50e × (1.6×10^-19 C/e) = -8.0×10^-18 C