AQA GCSE Physics key terms

The unit of electrical charge. One coulomb passes a point when a current of one ampere flows for one second.

The number of events recorded by a radiation detector each second.

The number of events recorded by a detector each second.

The rate of flow of electric charge, measured in amperes (A).

One complete repetition of an alternating pattern, returning to the same value and direction of change.

The name given to an unknown cause proposed to explain why the expansion of the universe is accelerating.

Matter that does not emit light but is inferred from its gravitational effects; its nature is not yet known.

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

Acceleration in the direction opposite to the object's velocity, causing its speed to decrease.

A change in an object's shape or size caused by forces.

Mass per unit volume of a substance, measured in kilograms per cubic metre.

The variable measured in response to the change in the independent variable.

The vertical distance from a point in a liquid to the liquid's surface.

A thin surface that vibrates when pressure variations in a sound wave reach it.

Reflection from a rough surface that scatters light in many directions.

A component that allows current to flow readily in one direction but has very high resistance in the reverse direction.

Current that flows in only one direction, although its size may vary.

A relationship in which multiplying one variable by a particular factor multiplies the other variable by the same factor.

A potential difference with a fixed polarity, so it acts in one direction only.

A relationship in which two quantities change by the same factor, represented by the symbol $\propto$.

A relationship in which one quantity increases by the same factor as another; its graph is a straight line through the origin.

The volume of fluid that is moved aside by the immersed part of an object.

The straight-line change in position in a stated direction. It is a vector quantity and can be found from the signed area under a velocity–time graph.

Energy that has spread into less useful stores, usually the thermal energy store of the surroundings.

The spreading of energy into less useful stores, usually the thermal energy stores of objects and their surroundings.

How far an object moves along its path, without a direction.

A graph showing how an object's total distance travelled changes with time.