Key terms & definitions

A charter first issued in 1215 that placed limits on royal power and protected specified rights. Edward I reconfirmed it during the political crisis of 1297.

A charter agreed by King John in 1215 that limited royal power and recognised certain rights, principally protecting powerful groups and free people.

A powerful, wealthy landowner near the top of Viking society.

A condition in which a plant lacks enough magnesium ions to make chlorophyll.

A mineral ion absorbed from the soil and needed by plants to make chlorophyll.

A material, object or device that produces a magnetic field and can exert magnetic forces.

A small magnet mounted so that it can turn and align with a magnetic field.

An instrument containing a small bar magnet that can turn to align with the local magnetic field.

The angle that Earth's magnetic field makes with the horizontal at a particular place.

The angle that a magnetic field makes with the horizontal; also called magnetic inclination.

A position on Earth’s surface where the magnetic field is vertical.

A small region within a ferromagnetic material in which many atomic magnetic effects are aligned in the same direction.

The production of a magnetic field around a conductor when an electric current flows through it.

A region in which a magnet or magnetic material experiences a force.

A region where a magnet or magnetic material experiences a force.

The direction in which a north magnetic pole would experience a force; outside a magnet, it is from north to south.

The direction of the force that would act on a north magnetic pole placed at a particular point.

An imaginary line used to show the direction of a magnetic field; lines drawn closer together indicate a stronger field.

A line used to represent a magnetic field. Its arrow shows the field direction, and the spacing between lines represents field strength.

A measure of how strong a magnetic field is at a particular point.

A measure of the strength of a magnetic field, represented by $B$ and measured in tesla (T).

A measure of magnetic field strength, represented by $B$ and measured in tesla (T).

A push or pull arising from an interaction between magnetic fields.

An attractive or repulsive non-contact force between magnetic poles.

The process by which a magnetic material becomes magnetised while it is in a magnetic field.

An attractive or repulsive interaction involving magnets or magnetic materials.

A material, such as iron, that can be attracted by a magnet and can become magnetised.

A material, such as iron, steel, cobalt or nickel, that is attracted to a magnet and can become magnetised.

One of the two ends of a magnet, where its magnetic force is strongest; the poles are called north and south.

A region of a magnet where the magnetic forces are strongest. A magnet has a north pole and a south pole.