A metallic sphere initially has a net charge of +4.0 nC. A negatively-charged rod initially has a net charge

Question

of –6.0 nC. When the rod touches the sphere 8.2 x109 electrons are transferred to the sphere. What is the
new net charge on the sphere?

Answer 1

q = Ne=- (8.2•10⁹•1.6•10⁻ ¹⁹)=
=- 1.36•10⁻⁹ C.
q(sph)+q =4•10⁻⁹ - 1.36•10⁻⁹ = + 2.64•10⁻⁹ C