How Many Electrons Are Removed from a Charged Copper Ball?

[Mek8388]

Homework Statement

A 3.0mm-diameter copper ball is charged to 50nC.What fraction of its electrons have been removed? The density of copper is 8900kgm^3.

Homework Equations

d=m/v; v=4/3* pi r^3

The Attempt at a Solution

I worked through it and got 5.682 E -16, but that answer was wrong. I first found the number of electrons were in it (3.125 E 11). I then found the volume (1.414 E -8), and I think that's where I got stuck after that.

 

[JaWiB]

So what did you try to do after that?

 

[Redbelly98]

Welcome to Physics Forums.

The Attempt at a Solution

I worked through it and got 5.682 E -16, but that answer was wrong. I first found the number of electrons were in it (3.125 E 11). I then found the volume (1.414 E -8), and I think that's where I got stuck after that.

Can you show the work you did to get those numbers? It would be easier to help you if you do that.