Question

Assume that in interstellar space the distance between two electrons is about 0.56 cm. The electric force between the two electrons is 1. Attractive. 2. Repulsive.

Answer 1

Answer: 2. Repulsive

The electric force is a force that is inversely proportional to the square of the distance. This can be proved by Coulomb's Law, which states:  

"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.

So, if we have two electrons, this means we have two charges with the same sign, hence the electric force between them will be repulsive.