Question

How many electrons make up a charge of - 30.0 μc?

Answer 1

Answer : The number of electrons are $1.91\times 10^{21}$

Explanation:

It is given that,

Charge, $q=-30\ \mu C=-30\times 10^{-6}\ C$

The mathematical expression for the quantization of the charge is given as :

q = n e

Where,

n is the number of electrons

e is the charge on the electrons.

$n=\dfrac{q}{e}$

$n=\dfrac{-30\times 10^{-6}\ C}{-1.6\times 10^{-19}\ C}$

$n=1.91\times 10^{21}$

Hence, this is the required solution.

Answer 2

Each electron has a charge of

$q=-1.6 \cdot 10^{-19}C$

In this problem, the total charge is

$Q=-30.0 \mu C=-30.0 \cdot 10^{-6} C$

Therefore, the number of electrons contained in this total charge will be given by the total charge divided by the charge of a single electron:

$N=\frac{Q}{q}=\frac{-30.0 \cdot 10^{-6} C}{-1.6 \cdot 10^{-19} C}=1.88 \cdot 10^{14}$