Glossary
Electromagnet
A type of magnet in which the magnetic field is produced by an electric current, typically by coiling a wire around a ferromagnetic core.
Example:
A junkyard crane uses a powerful Electromagnet to lift and move heavy scrap metal, turning off the current to release it.
Half-filled energy levels
Atomic orbitals that contain a single electron, which can lead to uncancelled electron spins and contribute to a material's magnetic properties.
Example:
In iron, the presence of half-filled energy levels allows its electrons' spins to align, making it a ferromagnetic material.
Magnetic Dipoles
Objects or systems that have two opposite magnetic poles, a north and a south, creating a magnetic field similar to that of a bar magnet.
Example:
Even a single electron acts as a tiny Magnetic Dipole due to its intrinsic spin.
Magnetic domains
Small regions within a ferromagnetic material where the magnetic moments of atoms are aligned in the same direction, acting like tiny magnets.
Example:
Heating a permanent magnet above its Curie temperature can randomize its magnetic domains, causing it to lose its magnetism.
Magnetic field lines
Imaginary lines used to visualize the direction and strength of a magnetic field, always flowing from the north pole to the south pole outside a magnet.
Example:
Iron filings sprinkled around a bar magnet will arrange themselves along the magnetic field lines, revealing the field's pattern.
Magnetic force (on a moving charged particle)
The force experienced by a charged particle when it moves through a magnetic field, perpendicular to both the velocity and the field direction.
Example:
The Magnetic force on electrons in a cathode ray tube causes them to deflect, steering the beam to create an image on the screen.
Permeability of free space (μ₀)
A fundamental physical constant representing the ability of a vacuum to support the formation of a magnetic field, used in equations for magnetic field strength.
Example:
The value of Permeability of free space (μ₀) is a constant that appears in Ampere's Law and the Biot-Savart Law, linking current to magnetic fields.
Right-Hand Curl Rule (RHCR)
A mnemonic used to determine the direction of the magnetic field around a current-carrying wire, where the thumb points in the direction of current and curled fingers show the field's direction.
Example:
Applying the Right-Hand Curl Rule to a wire with current flowing upwards, you'd find the magnetic field circles counter-clockwise around the wire.
Right-Hand Rule (RHR)
A mnemonic used to determine the direction of the magnetic force on a positive moving charge, where the thumb points to velocity, fingers to the magnetic field, and the palm indicates the force.
Example:
Using the Right-Hand Rule, you can quickly determine that an electron moving into a magnetic field pointing right will experience an upward force (then reverse for negative charge).
Teslas (T)
The SI unit for magnetic field strength (B), defined as one Newton per ampere-meter (N/(A·m)).
Example:
A strong MRI machine can generate a magnetic field of several Teslas, powerful enough to align the protons in your body.