micro = 10^-6
n = nano = 10^-9
(a) -2.5 micro coulombs = -2.5 X 10^-6
The charge on a electron is always -1.60 X 10^-19.
So, given charge divided by charge on electron gives you number of electrons.
(-2.5X10^-6)/(-1.60X10^-19) = 1.5625 X 10^13 excess electrons.
(b) -2.5 nano coulombs = -2.5 X 10^-9
The charge on a electron is always -1.60 X 10^-19.
So, given charge divided by charge on electron gives you number of electrons.
(-2.5X10^-9)/(-1.60X10^-19) = 1.5625 X 10^10 excess electrons.
Round my answers to 3 significant figures if needed or to the appropriate form asked by the question.
