Please help me out. :)

How many excess electrons must be placed on each of two spheres 3cm apart if the force of repulsion between the spheres is 10^-19 N?

Question

Please help me out. :)

How many excess electrons must be placed on each of two spheres 3cm apart if the force of repulsion between the spheres is 10^-19 N?

ganeshie8 · Answer

use coulomb's law ?

ganeshie8 · Answer

say you need to put `q`  amount of charge on each of the spheres :

$$F = 9\times 10^9 ~ \dfrac{q\times q}{r^2}$$

plugin the given values and solve $q$

anonymous · Answer

ahh.. okay.. :) wait..

ganeshie8 · Answer

take ur time, make sure you convert the distance to appropriate unit : meter

anonymous · Answer

sure.. thanks for reminding me. :)

anonymous · Answer

the value of q is 1 x 10^-16..
I'll convert it to e- .. so my final answer is 624.22 e- :)
am I right? :)

ganeshie8 · Answer

wolfram says $\large  q = 3 \times  10^{-16}$ ?