Question

According to Coulomb’s Law which of the following statements are correct? Select all that apply.
The force between two charged objects increases as the charge of either one of the objects is increased.
The force between two charged objects decreases as the charge of either one of the objects increases.
The force between two charged objects increases as the objects are pulled further apart.
The force between two charged objects increases as the objects are placed closer together.
Two objects that are negatively charged will always produce greater forces than two objects that are positively charged.

Answer 1

The correct options are:
1) The force between two charged objects increases as the charge of either one of the objects is increased. 
4) The force between two charged objects increases as the objects are placed closer together. 

In fact, the electrostatic force is given by Coulomb's law:
$F=k \frac{q_1 q_2}{r^2}$
where k is the Coulomb's constant, q1 and q2 are the two charges, r is the separation between the two charges. As we can see from the equation, if one of the charges (q1 or q2) is increased, than the force increases as well (so statement 1) is correct), and if the two objects are placed closer together (r is decreased), the force F increases as well (so statement 4 is correct as well)

Answer 2

the force between two charged objects increases as the charge of either one of the object is increased


the force between two charged objects increases as the object are placed closer together

is the right answer