Question

Common static electricity involves charges ranging from nanocoulombs to microcoulombs. How many electrons are needed to form a charge of -2.00 nC?

Answer 1

To solve this problem we will use the ratio given by the amount of total charge (q) equivalent to the individual charge of each electron (e) multiplied by the total number of electrons (n) present, that is,

$q = ne$

Here

q = Total charge

e = Electron charge

Our value of the charge is

$q = -2nC= -2*10^{-9}C$

We know that the charge in a electron is

$e = -1.6*10^{-19}C$

Replacing we have then

$(-2*10^{-9}) = n(-1.6*10^{-19})$

$n = \frac{-2*10^{-9}}{-1.6*10^{-19}}$

$n = 1.25*10^{10} electrons$

Therefore the number of electrons needed to form a charge of -2nC is $1.25*10^{10} electrons$