Question

If two particles have equal charges and are placed near one another, how
will they move?
OA) They won't move.
OB) The two particles will move toward each other.
OC) The two particles will move away from each other.

Answer 1

Answer: C) The two particles will move away from each other

Explanation:

When two electrically charged bodies come closer, appears a force that attracts or repels them, depending on the sign of the charges of this two bodies.

This is stated by Coulomb's Law:

"The electrostatic force $F_{E}$ between two point charges $q_{1}$ and $q_{2}$ is proportional to the product of the charges and inversely proportional to the square of the distance $d$ that separates them, and has the direction of the line that joins them"  

Mathematically this law is written as:  

$F_{E}= K\frac{q_{1}.q_{2}}{d^{2}}$  

Where $K$ is a proportionality constant.  

Now, if $q_{1}$ and $q_{2}$ have the same sign charge (both positive or both negative), a repulsive force will act on these charges.