A person scuffing her feet on a wool rug on a dry day accumulates a net charge of -62 µC.?

Question

How many excess electrons does this person get?
By how much does her mass increase?

Answer 1

The charge on the electron e = -1.602 x 10-19 C. The person in your problem has accumulated -62 x 10-6 C. The number of electrons required to produce this charge is

-62 x 10-6 C / -1.602 x 10-19 C / electron

The mass of the electron is 9.11 x 10-31 kg. Multiply the number you just got by that mass to find the increase in mass ( hint - not much ).