Physics key terms

The power at which an appliance is designed to operate normally; it states how many joules the appliance transfers each second.

The closeness of repeated measurements to one another.

A statement of what should happen in a specified situation if an explanation is correct.

A symbol placed before a unit to show that the unit has been multiplied by a particular power of ten.

The normal force acting per unit area of a surface.

The change in pressure between two positions, measured in pascals (Pa).

Repeated changes in pressure that travel through a medium as a sound wave.

A relationship for a fixed mass of gas at constant temperature in which pressure multiplied by volume remains constant: $P_1V_1=P_2V_2$.

The input coil of a transformer, connected to the alternating supply.

The potential difference across a transformer coil connected to the input supply.

The straight reference line passing through the optical centre and the principal foci of a lens.

The point where rays parallel to the principal axis meet after passing through a convex lens, or appear to come from after passing through a concave lens.

The frequency at which an object's emitted radiation is strongest.

The rule that, for a balanced object, the total clockwise moment about a pivot equals the total anticlockwise moment about that pivot.

The chance that a particular outcome will occur.

An estimate of what may happen in the future, based on evidence and assumptions available at the time.

The characteristics used to describe or identify a material, such as its state, melting point, density and chemical behaviour.

A relationship in which quantities change by the same multiplicative factor.

A positively charged particle found in an atom’s nucleus.

The number of protons in a nucleus; it determines the element and its nuclear charge.

A forming star made of gas drawn together by gravity, before sustained hydrogen fusion begins in its core.

The opinions and attitudes held by members of the public, which may influence political decisions and whether new power stations are accepted.

A longitudinal seismic wave that can travel through solids and liquids.

The quantity of electric charge transferred past a point; its symbol is $Q$ and its unit is the coulomb (C).

The use of reflected electromagnetic waves to detect an object and determine information such as its position.

Energy transferred by waves or particles emitted from a source.

A balance in which radiation is absorbed and emitted at the same rate, so there is no temperature change due to radiation.

A measure of the biological effect produced when ionising radiation is absorbed; AQA gives the sievert (Sv) as its unit, although students do not have to recall this unit.