Edexcel GCSE Physics key terms

The rate of flow of electric charge through a conductor, represented by $I$ and measured in amperes (A).

A graph showing how the current through a component changes as the potential difference across it changes.

One complete repetition of a wave or vibration.

A device that records measurements from sensors, such as the times reported by light gates.

One of the two smaller nuclei formed when a larger nucleus undergoes nuclear fission.

Acceleration opposite to an object's velocity, causing its speed to decrease.

The number of places written to the right of a decimal point.

The controlled closure and dismantling of a power station at the end of its working life.

A change in an object's shape caused by forces, such as stretching, compression or bending.

Mass per unit volume, usually measured in kilograms per cubic metre (kg/m³).

The physical change in which a gas changes directly into a solid without first becoming a liquid.

The vertical distance of a point below the surface of a fluid.

A unit formed by combining base units through multiplication or division, sometimes given a special name such as the newton.

A thin flexible part that vibrates when sound waves produce changing pressure on it.

The unequal absorption of different wavelengths by a material.

Reflection from a rough surface in which parallel incident rays leave in different directions.

Describes an image that is smaller than its object.

A component that allows current to flow readily in one direction but strongly opposes it in the other.

The unit of lens power, symbol D; one dioptre is one reciprocal metre.

An electric current in which charge moves in one direction only.

The way in which a vector acts or points, stated using words, a bearing or a sign relative to a chosen positive direction.

The direction in which a wave and its energy propagate away from the source.

A relationship in which one quantity changes by the same factor as another quantity.

A voltage that keeps the same polarity, so one terminal remains positive relative to the other.

Liquid or gas moved out of the space occupied by an immersed object.

The change in position from a starting point in a stated direction; it is a vector quantity.

Energy transferred to less useful stores, often spreading into the surroundings by heating.

The spreading of energy into the surroundings so that it becomes less useful.