Question

A sphere is charged with electrons to

−7 × 10−6 C.
How many electrons make up this charge?
The elemental charge is 1.6 × 10−19 C.

Answer 1

`4.38\cdot 10^(13)` electrons

Step-by-step explanation:

The net charge on the sphere is equal to:

`Q=-7\cdot 10^(-6)C`

This charge is made up of N electrons. Each electron carries a charge of

`q=-1.6\cdot 10^(-19)C`

So the total charge is just the number of electrons times the charge of each electron:

`Q=Nq`

And solving the equation for N, we find the number of electrons:

`N=(Q)/(q)=(-7\cdot 10^(-6)C)/(-1.6\cdot 10^(-19) C)=4.38\cdot 10^(13)`