Two parallel wires carrying current in the same direction attract each other while two beams of electrons travelling in the same direction repel each other. Why?

The behavior of parallel wires and beams of electrons can be explained through the principles of electromagnetism and electric charge interactions.

Current-Carrying Wires

When two parallel wires carry current in the same direction, they create magnetic fields around themselves. According to Ampère's law, these magnetic fields interact with each other. The magnetic field produced by one wire exerts a force on the other wire, resulting in an attractive force. This attraction occurs because the magnetic field lines from both wires are oriented in a way that pulls them together.

Electron Beams

In contrast, electrons are negatively charged particles. When two beams of electrons travel in the same direction, they repel each other due to the electrostatic force. Like charges repel, so the negative charges in each beam push away from one another, leading to a repulsive interaction.

Key Differences

• Wires: Attract due to magnetic fields created by the current.
• Electron Beams: Repel due to electrostatic forces between like charges.

In summary, the attraction between current-carrying wires arises from their magnetic interactions, while the repulsion between electron beams is due to their electric charge properties. Understanding these principles helps clarify the different behaviors of currents and charged particles.