Magnetism and Magnetic Phenomena

Comprehensive vocabulary flashcards covering the key principles of magnetism, magnetic vs non-magnetic materials, domain theory, magnetisation and demagnetisation methods, soft vs hard magnetic materials, magnetic fields, and magnetic shielding.

Earth's Magnetic South Pole

The geographic North Pole of the Earth, which attracts the north-seeking pole of a magnet or compass needle because opposite magnetic poles attract.

Magnetic Materials

Materials that are attracted by a magnet and can be magnetised, such as cobalt, iron, nickel, steel, alnico, and neodymium.

Non-magnetic Materials

Materials that are not attracted by a magnet, including aluminium, brass, copper, gold, silver, glass, plastic, and wood.

Repulsion Test

The only definitive test to confirm that an unknown object is a magnet, because attraction can occur between two opposite poles or between a magnet and an unmagnetised magnetic material.

Magnetic Domains

Microscopic regions within a magnetic material containing atomic magnets that align together to produce a net magnetic field.

Unmagnetised State

The condition of a magnetic material where its magnetic domains point in random directions, resulting in zero net magnetic effect.

Magnetised State

The condition of a magnetic material where its magnetic domains are aligned in the same direction (tip to tail), creating net North and South poles at opposite ends.

Induced Magnetism

The process by which a magnetic material temporarily becomes a magnet when placed close to, in contact with, or inside the magnetic field of a strong magnet or current-carrying solenoid.

Stroking Method

A technique for inducing magnetism where an unmagnetised steel bar is repeatedly stroked in one direction using the same pole of a permanent magnet, which is lifted high above the bar after each stroke.

Electrical Magnetisation (DC Solenoid)

A method of magnetising a material by placing it inside a solenoid carrying direct current (DC), where the solenoid's magnetic field aligns the domains within the material.

Electrical Demagnetisation (AC Solenoid)

A method of demagnetising a magnet by placing it in an east-west direction inside a solenoid powered by alternating current (AC) and slowly withdrawing it while the current flows.

Iron Keepers

Soft iron pieces placed across the poles of stored permanent magnets to provide a closed loop path for magnetic field lines, preserving magnetic strength and preventing demagnetisation.

Soft Magnetic Material

A magnetic material (such as soft iron) that is easily magnetised and demagnetised, does not retain magnetism, and is used in temporary magnets like electromagnets, circuit breakers, electric bells, and junkyard cranes.

Hard Magnetic Material

A magnetic material (such as alnico, neodymium, or steel) that is difficult to magnetise and demagnetise, retains magnetism long term, and is used for permanent magnets like magnetic door catches and refrigerator strips.

Magnetic Field

A region in space where a magnetic object experiences a magnetic force at a distance without direct physical contact.

Plotting Compass Field Tracing

A method of mapping magnetic field lines around a magnet by recording the direction indicated by the north-seeking needle of a compass placed at successive positions.

Magnetic Field Lines

Continuous loops representing a magnetic field that point out of the North Pole and into the South Pole outside a magnet, continuing through the inside of the magnet.

Uniform Magnetic Field

A magnetic field in which field lines are equally spaced and parallel, resulting in a constant magnetic force throughout the region.

Non-uniform Magnetic Field

A magnetic field in which field lines are not equally spaced and not parallel, producing varying magnetic forces at different points.

Neutral Point (Region X)

A point or region between two repelling like poles where opposing magnetic fields are equal in magnitude and opposite in direction, resulting in a net magnetic field of zero.

Joined Magnets Combined Force

The net magnetic field produced when two bar magnets are joined end-to-end, which is stronger than a single bar magnet but weaker than the arithmetic sum of two separate bar magnets because the effective poles are placed further apart.

Magnetic Shielding

The technique of surrounding sensitive equipment with thin sheets or closed hollow containers of soft magnetic material to divert magnetic field lines away from the internal region.