Magnetism Vocabulary Flashcards (Video Notes)

Vocabulary flashcards covering key magnetism concepts from the lecture notes, including magnets, poles, magnetic fields and visualization, and the right-hand rule.

Magnetism

A long-range force associated with magnets; magnets have north and south poles (dipoles) and exert forces on each other and on magnetic materials.

Magnetic dipole

A magnet's two poles (north and south); the basic unit of magnetism; cutting a magnet yields two weaker dipoles.

Magnetic poles

The north and south ends of a magnet; like poles repel and opposite poles attract; north pole is usually shaded in drawings.

North magnetic pole

One of the two magnetic poles; repels known north poles and attracts known south poles.

South magnetic pole

The other magnetic pole; attracts known north poles and repels known south poles.

Compass

A device that uses a magnetic field to identify pole directions; its north end is usually shaded.

Magnetic material

Material attracted to magnets; iron is the most common example; attracted to both poles via induced dipoles.

Induced dipole

A temporary dipole in a material caused by an external magnetic field, leading to attraction to the magnet.

Magnetic field

The region around magnets where magnetic forces act; visualized by field lines or compass needles; around a straight current, lines form circles.

Magnetic field lines

Imaginary lines showing the direction of the magnetic field; start at the north pole and end at the south pole; do not cross; density indicates field strength.

Field line density

Closer field lines indicate stronger magnetic field; lines spread out as you move away from the magnet, indicating weakening field.

Two magnets (unlike poles facing)

Field lines start at the north of one magnet and end at the south of the other; lines follow the shortest path and do not cross.

Two magnets (like poles facing)

Field lines curve away from the near north pole to avoid other north poles; lines cannot cross and appear to repel.

Multiple poles

A magnet can have more than one north–south pair; poles may not be at the ends; e.g., a strip fridge magnet.

Earth's magnetic field

Planetary magnetic field; geographic north corresponds to magnetic south; the south magnetic pole lies near northern Canada.

Geographic north vs magnetic pole

Geographic north pole aligns with Earth's magnetic south pole; the magnetic pole is near northern Canada.

Electric currents create magnetic fields

A current in a long straight wire produces circular magnetic field lines around the wire; no fixed north/south poles—just loops.

Right-hand rule

Method to determine magnetic field direction around a current: point the thumb along current, wrap fingers to indicate field direction.

Dipole field around a loop

A circular current loop creates a dipole-like magnetic field; field lines form closed loops and resemble a bar-magnet field at a distance.

Field visualization with iron filings

Iron filings align with the magnetic field, revealing the pattern of field lines and their strength.

Field visualization with compass needles

Tiny compass needles align with the local magnetic field, illustrating the field flow around magnets or wires.

No field line crossing

Magnetic field lines never cross; they define a unique field direction at every point.

Field strength vs distance

Magnetic field strength decreases with distance from the source (magnet or current).

Fridge magnet polarity

Fridge magnets can show multiple north–south poles across their surface; poles do not need to be at the ends.