Question

wo charged spheres are 1.5 m apart and are exerting an electrostatic force (Fo) on each other. If the charge on each sphere decreases by a factor of 9, determine (in terms of Fo) how much electrostatic force each sphere will exert on the other.

Answer 1

F0 / 81

Step-by-step explanation:

Let the two charges by Q and q which are separated by d.

By use of coulomb's law

F0 = k Q q / d^2 ......(1)

Now the charges are decreased by factor of 9.

Q' = Q / 9

q' = q / 9 ......(2)

Now the Force is

F' = k Q' q' / d^2

F' = k (Q /9) (q / 9) / d^2

F' = k Q q / 81d^2

F' = F0 / 81