+5 nC converted to # electrons

1. Feb 9, 2006

MathGnome

Ok, for some reason, I'm getting the wrong answer. It's asking for how many electrons were removed from an object that has gained a +5nC charge. Here's my setup.

(1.60x10^(-19)) / ( 5*10^(-9))
I'm getting 3.2*10^(-11)
yet book says the answer is actually 3.13*10^(-10)

wtf?

2. Feb 9, 2006

quasar987

Well both the book and you are wrong.

If you want wow many electrons are in 5nC, the correct division is 5nC/e. You did e/5nC. The book only has a sign error in the exponent.

You should have gotten a clue that the book answer was wrong, as 3.13*10^(-10) is less than 1 electron and it is a law of nature that you can only mova around charges in amounts multiple of e (until we find how to separate quarks from hadrons that is).

Last edited: Feb 9, 2006
3. Feb 9, 2006

chroot

Staff Emeritus
Look at your units. Make sure they cancel, as shown below.

$5\,\textrm{nC} \cdot \frac{1 \,\textrm{electron}}{1.6 \cdot 10^{-19} \,\textrm{C}} = x \, \textrm{electrons}$

- Warren