Physics key terms

A planned sequence of actions for making observations or collecting data to answer a scientific question.

An event in which one object, or a group of connected objects, separates into parts that move apart.

A decrease in which the amount lost per unit time becomes progressively smaller, producing a curved graph.

The increase in an object’s length compared with its original, unloaded length.

Treatment in which high-energy radiation beams are directed at a tumour from equipment outside the body.

Contamination on the surface of an object or the outside of the body.

A force exerted on the chosen object or system by something outside its boundary.

An estimate read from a graph beyond the range of measured values.

A current that flows along an unintended path because of a fault in an electrical system.

A material, such as iron, cobalt or nickel, that responds strongly to a magnetic field and can itself be magnetised.

A region in which an object can experience a force without touching the source of that force.

A thin wire inside a filament lamp that becomes hot enough to emit light when current passes through it.

A lamp containing a thin wire that becomes hot enough to glow when current passes through it.

Energy used directly by people and businesses in activities such as heating, transport and operating machinery.

The velocity at the end of the period of motion being considered, represented by $v$.

The smaller daughter nuclei formed when a heavy nucleus splits.

A sample of gas in which no gas particles enter or leave, so its mass and number of particles remain unchanged.

A circuit component whose resistance is designed to remain constant under fixed physical conditions.

A hand rule that relates the mutually perpendicular directions of magnetic field, conventional current and force on a current-carrying conductor.

A substance that can flow and may be either a liquid or a gas.

The emission of visible light by a substance after it has absorbed radiation such as ultraviolet.

The distance along the principal axis from the centre of a lens to its principal focus.

A push or pull on an object caused by an interaction with another object.

A condition in which the vector sum of the forces is zero, so there is no resultant force and no acceleration.

A graph of applied force against the resulting extension; the area beneath it represents the work done in stretching.

A device that produces a larger output force than the force applied to it.

A pulling interaction that tends to keep particles close together.