Final answer:
Electrostatic repulsion occurs between like-charged objects due to Coulomb's Law and diminishes with distance. In an electroscope, conductor movement reduces electrostatic repulsion and causes the leaves to come closer. An electrostatic repulsion graph illustrates the inverse relationship between force and distance.
Step-by-step explanation:
The reason for electrostatic repulsion is due to the interaction between particles or objects with like electrical charges. According to Coulomb's Law, which was proposed by French physicist Charles Coulomb, charged objects exert a force on each other that is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. This means that two positively charged or two negatively charged objects will repel each other, and this repulsive force diminishes with increasing distance.
When a conductor is moved between the plastic sheets of a charged electroscope, the leaves of the electroscope will move closer together. This occurs because the conductor allows charges to move freely and redistribute themselves, effectively cancelling out the external electric fields between the sheets which results in a decrease in the electrostatic repulsion between the leaves.
An electrostatic repulsion graph would typically show the magnitude of the repulsive force as a function of the distance between two like-charged objects. This graph would demonstrate that as the distance increases, the force decreases sharply, in accordance with Coulomb's Law.