# How many extra electrons does the toner particle carry?

## Homework Statement

A photocopier imaging drum is positively charged to attract negatively charged toner particles. Near the surface of the imaging drum, the E field has a magnitude of 1.90 × 105 N/C
A. What must be the be the magnitude of the negative charge on a toner particle of mass 2.80 × 10 -12 kg if it is to be attracted to the drum with a force that is 10.0 times its weight?
B. How many extra electrons does the toner particle carry?

## Homework Equations

I have already figured out A with F=qe and W=mg
That answer came out to be = 1.44E-15 C
I cant figure out B. How many extra electrons does the toner particle carry?

## The Attempt at a Solution

The answer here is 9.03E+3 but I dont know how that is the right answer, can someone please explain? I feel like it is probably just a formula, but i dont know it

collinsmark
Homework Helper
Gold Member
B. How many extra electrons does the toner particle carry?

I have already figured out A with F=qe and W=mg
That answer came out to be = 1.44E-15 C
I cant figure out B. How many extra electrons does the toner particle carry?

## The Attempt at a Solution

The answer here is 9.03E+3 but I dont know how that is the right answer, can someone please explain? I feel like it is probably just a formula, but i dont know it

So you know the total charge is -1.44 x 10-15 Coulombs.

The next thing to ask yourself is how much charge (i.e. how many Coulombs) is carried by a single electron? (You can look this up if you haven't memorized it.) [Edit: And welcome to Physics Forums, jbirse!]

Thanks! I knew it was probably pretty simple, but I was just unsure of what to exactly do. thanks