# Static Electricity, Spheres question

1. Apr 15, 2012

### vaironl

1. The problem statement, all variables and given/known data
Suppose you have two isolated conducting spheres that are both neutral. You move 2mC of charge from one to the other.

a. What is the charge now on each sphere?
My solution: One sphere is positively charged with 2mC more protons, while the other is negatively charged with 2mC more electrons.
Comments: What is mC? I know C is the SI unit of charge but I cannot find mC.
megaCoulomb?

b. What is the charge difference between them?
My solution: 2mC

c. What is the force between the spheres, if the centers of the spheres are 1.3m apart?
Relevant information: $\frac{k*q1*q2}{d^2}$

k= 8.99 * 109Nm2/C2
Solution: Felectric = $\frac{(8.99*10^9)(2*10^6C)^2}{1.3^2}$
= 2.13 * 1022N

2. Apr 15, 2012

### tiny-tim

hi vaironl!

("m" is always "milli-'', as in mg, mm, or ms )
suppose you have two plates each with equal numbrs of apples and pears

you move two apples from one plate to the other …