Final answer:
The repulsion between two positively charged particles is caused by the electric force, which is a fundamental force of nature described by Coulomb's law.
Step-by-step explanation:
The force responsible for the repulsion between two positively charged particles is electric force. According to Coulomb's law, like charges repel each other, which means that positive charge interacting with another positive charge results in a repulsive force. This is one of the four fundamental forces of nature and explains the behavior of charges and their interactions.
For the questions provided for reference, the answers are as follows:
- The force responsible for holding an atom together is the electric force (b).
- The phenomenon that correctly describes the direction and magnitude of normal forces is electromagnetic repulsion (b).
- When two positive point charges interact, the force between them is repulsive and acts along the line joining the two point charges (c).