Question

A sphere has with a charge of +6.4 milli-coulombs is placed on an insulating stand.
a. How many elementary charges does this represent?
b. Does this charged sphere have a lack of electrons or an excess of electrons relative to its neutral state? (Explain)

Answer 1

a)

$$n=\frac{q}{e}=\frac{6.4\cdot10^{-6}}{1.6\cdot10^{-19}}=4.0\cdot10^{13}$$

b) Electon has negative charge, thus this positively-charged sphere have a lack of electrons relative to its neutral state.