Magnetism Basics: Fundamental Principles

Magnetism: Exploring Fundamental Principles

• Magnetism arises from electric currents.
• Moving charges (like in a current-carrying wire) create a magnetic field.

Magnetic Fields Produced by Currents

• The direction of a magnetic field can be predicted using the right-hand rule.
• The thumb points in the direction of the current; curled fingers indicate magnetic field lines.
• The strength of the magnetic field is stronger with a larger current, and weaker further from the wire.

Force Between Parallel Wires

• Attractive force: Parallel wires with current flowing in the same direction experience an attractive force.
• Repulsive force: Parallel wires with current flowing in opposite directions experience a repulsive force.
• The current flowing through a wire creates a magnetic field, and this field interacts with a second wire's current, resulting in a force.

Ampere's Law

• Relationship: Ampere's law describes the link between magnetic fields and the electric currents causing them.
• Line Integral: The line integral of a magnetic field around a closed loop is proportional to the total current enclosed by the loop. This is a key mathematical relationship to calculate magnetic fields.
• Applications: Understanding and calculating magnetic fields in various systems, such as solenoids and electromagnets.

Solenoids: Creating Strong Magnetic Fields

• Description: A solenoid is a coil of wire shaped like a helix.
• Strong Uniform Field: When electric current flows through a solenoid, a strong, uniform magnetic field is created inside of the coil.
• Electromagnets: Solenoids are commonly used to create electromagnets. The strength of the electromagnet's magnetic field can be controlled by adjusting the current.
• Applications: Solenoids are used in various applications, including electric motors, magnetic levitation, and medical imaging.