A metal sphere has a charge of +8.0 µC. What is the net charge after 7.0 x1013 electrons have been placed on i

Answer 1

You have a sphere with charge +8 x 10^-6 Coloumbs.

7 x 10^13 electrons (each with charge 1.6 x 10^-19) are put on it.

(7 x 10^13) x (1.6 x 10^-19) = 1.12 x 10^-5 Coloumbs.

(8 x 10^-6) - (1.12 x 10^-5) = -3.2 x 10^-6 Coloumbs

Enough electrons have been put on the sphere to make its potential negative.