Two charges Q1 and Q2 are separated by a distance d'' and exert a force f'' on each other?

Question

What new force would exist if Q1 is doubled 1) 4F, 2) 1/4F, 3) 1/2F, 4) 2F or 5) 0

Answer 1

#4) 2F

Electromatic force can be calculated using Coulomb's Law. If we're only worried about the magnitude of the force, and not the direction, we can use a scalar version of the law, which only deals with the magnitude:

F = Kc (q1 * q2) / r^2 where:

F is the force between the two charges,
Kc is the electrostatic constant, a universally constant value,
q1 is the charge of the body,
q2 is the charge of the second body,
and r is the distance between the charges.

Without getting too complicated, we can see that the value F will change linearly with the values of q1 and q2. ie: If q1 or q2 is doubled, F will be doubled. If q1 or q2 is divided by two, F will be halved.

Because we divide these numbers by the square of the distance, distance is an inverse square function to F. ie: If r is divided by two, F will be multiplied by four. If r is multiplied by two, F will be divided by four, etc.