# Find the Magnitude

## Homework Statement

A nickel coin has a mass of about 4.3g. Each mole (6.02e23 atoms) has a mass of about 58.2g

## Homework Equations

I found the number of electrons on each coin, which is 1.245e24 and also the number of atoms on the coin which is 4.447e22.

## The Attempt at a Solution

Now I have to find the magnitude of the charge of all of these electrons. I just started phys part two and need help. I Know that the C constant is, and I think I have to use the F=Q1Q2/r2but I can't come up with the solution

LowlyPion
Homework Helper
Welcome to PF.

By C I think you mean the units of charge - Coulomb.

The formula you show is for the force between charges separated by a distance.

If you are looking for total charge in C, however, you will want to look up how many electrons makes up a Coulomb.

Well, I know that C=6.02 x 10^18 electrons, and I have 1.245 x 10^24 electrons, also the problem states that there are 28 electrons/atom on the nickel coin... would I multiply those?

LowlyPion
Homework Helper
Well, I know that C=6.02 x 10^18 electrons, and I have 1.245 x 10^24 electrons, also the problem states that there are 28 electrons/atom on the nickel coin... would I multiply those?

You might want to use 6.24*1018 electrons/ Coulomb.
http://en.wikipedia.org/wiki/Coulomb

As to the 28 per atom, didn't you use that already to determine total electrons?

yes, that was to find the total electrons

LowlyPion
Homework Helper
yes, that was to find the total electrons

So if you have total electrons and you know how many are in a Coulomb ...

I think i have to multiply but I'm not coming out with the right answer

LowlyPion
Homework Helper
I think i have to multiply but I'm not coming out with the right answer

If I have 48 eggs, and there are 12 eggs in a dozen, and I wanted to know how many dozen I had, ... I wouldn't be multiplying.

Ok, cool...got it thanks