Electric Field Strength: Calculating for 0.75 g Plastic Bead

[BuBbLeS01]

Electric field...please help!

Homework Statement

A 0.75 g plastic bead is charged by the addition of 8.28×10^10 excess electrons. What electric field (strength) will cause the bead to hang suspended in the air?

Homework Equations

The Attempt at a Solution

Doesn't E have to equal the weight? So would I just calculate the weight of the bead? That seems to easy though...

 

[Shooting Star]

The weight and the charge. Also, remember Force = E*q.

 

[BuBbLeS01]

So...
(K*Q1*Q2) / R^2 = (KQ1) / R^2 * Q
And then I solve for Q?
But then I get Q2 = Q?? I am confused...

 

[Shooting Star]

Let E be the unknown electric field. Then what is the force it exerts on a charge q? I've already told you...

 

[BuBbLeS01]

E = Force / Q
Force = K*Q1*Q2 / r^2