Repulsion between two small spheres

[objective33]

Homework Statement

Calculate the force of electric repulsion between two small spheres placed 1.0 m apart if each has a deficit of 1.0 x 10^8 electrons.

Homework Equations

N = q/e
qe = mg
q = mg / e
q = mgr / Vb
e = 1.602 x 10^-19 C.
k = 9 x 10^9 - not sure if relevant or not.
Fe = qe
Answer ( as stated in the textbook): 2.3 x 10^-12N

The Attempt at a Solution

Fe = qe?
r = 1. 0 m
e constant used
g = 9.8 N/kg?
Fe = (1.0 x 10^8 C)( 1.6 x 10^-19 C)x (1.0m/9.8N/kg) = 1.63 x 10^-12 N.

 

[objective33]

Through my reasoning, I found the answer.


Charge of one electron = 1.602 x 10^-19 C
Charge of a sphere = 1.602 x 10^-19 x 1.0 x 10^8 C

F = (1/4piÈ) Q1Q2/d^2
(1/4piÈ) is a constant equal to 9 x 10^9
F = 9x10^9 x (1.602x10^-11) x (1.602x10^-11) / 1
F = 2.3 x 10^-12 N