AQA GCSE Physics key terms

The rate at which velocity changes, measured in metres per second squared (m/s²).

The closeness of a measurement to the true value.

Rain made more acidic by pollutants in the atmosphere, including sulfur dioxide from burning sulfur-containing fuels.

The number of radioactive decays occurring per second in a sample, measured in becquerels (Bq). One becquerel means one decay per second.

A particle consisting of two protons and two neutrons, represented as $^4_2\text{He}$ or $^4_2\alpha$.

An experiment in which alpha particles were directed at thin metal foil and their scattering was observed.

A current that repeatedly reverses direction.

Current that repeatedly reverses direction.

A potential difference whose polarity repeatedly reverses, usually while its magnitude also varies.

A generator that produces alternating current.

Height above a reference level, such as sea level.

A meter connected in series to measure current in amperes.

The unit of electric current. One ampere means that one coulomb of charge passes a point each second.

The maximum displacement of a point on a wave from its undisturbed position.

A result that differs substantially from the pattern formed by the other results.

A human-made object placed in orbit around a body such as Earth.

The thin layer of air surrounding the Earth, held there by gravity.

The force per unit area exerted on a surface by air molecules colliding with it.

The number of protons in a nucleus, written at the lower left of a nuclide symbol; it determines the element.

A force that pulls objects towards one another.

The total change in velocity divided by the time over which that change occurs.

The total distance travelled divided by the total time taken.

Ionising radiation that is always present in the surroundings, originating from both natural and artificial sources.

Two or more cells connected together, shown by repeated long–short line pairs.

The unit of activity; one becquerel means one nuclear decay per second.

A high-speed electron emitted from a nucleus when a neutron changes into a proton, represented as $^0_{-1}\text{e}$ or $^0_{-1}\beta$.

The model that the universe began in a very small, extremely hot and dense state and has expanded.