Question: Looking down onto Coulomb's torsion balance, we see a rod 2cm long suspended from a thin filament as shown in the diagrams of the following table:
a. Write down Coulomb's law and define the symbols you use and their units.
b. Explain and show in what way Coulomb's data given in the table support his law. Be quantitative.
c. If the charge on each tiny sphere was 1nC, what would be the force between the two charges in diagram (i) of the table?
d. What would be the electric field acting on the charge at the end of the needle in (i)?
e. By how much would that field change if we doubled the charge at the end of the needle but left the other charge unchanged?