How does the magnitude of the electrical force between a pair of charged objects change when the objects are moved twice as far apart?

The magnitude of the force decreases by a factor 4

Explanation:

The magnitude of the electrical force between a pair of charged objects is given by

where

k is the Coulomb's constant

q1, q2 are the charges of the two objects

r is the distance between the two objects

In this problem, the two objects are moved twice as far apart, so their distance becomes

r' = 2r

Substituting into the equation, we find the new force