OCR GCSE Physics A key terms

The downward acceleration of an object in free fall; near the Earth’s surface its magnitude is about $9.8\ \text{m/s}^2$, commonly rounded to $10\ \text{m/s}^2$.

The number of nuclear decays occurring each second, measured in becquerels (Bq).

A conductor used to transmit or receive electromagnetic waves.

A positively charged particle used to probe atoms in the gold-foil experiment.

Current that repeatedly reverses direction.

A potential difference that repeatedly reverses polarity, usually changing continuously with time.

A generator that produces alternating current by converting mechanical energy into electrical energy.

Height above a stated reference level, commonly sea level.

A meter connected in series to measure current.

The unit of electric current, with symbol A.

The maximum displacement from the equilibrium position, measured in metres for a displacement wave.

The angle between an incident ray and the normal at the point where the ray meets a surface.

The angle between a reflected ray and the normal.

A result that is noticeably different from the pattern of the other repeat measurements.

The upward force on an object in a fluid equals the weight of the fluid it displaces.

A human-made object placed in orbit around a body in space.

The mixture of gases surrounding the Earth.

The force exerted by the atmosphere per unit area of a surface.

The smallest particle of an element that can take part in chemical changes.

A number equal to the number of protons in a nucleus, written at the lower left of a nuclide symbol; it identifies the element.

The detection and perception of sound by the ear, auditory nerve and brain.

The total mass of an object divided by its total volume, including any hollow spaces within it.

The overall distance travelled divided by the overall time taken.

Balanced forces are forces on one object that combine to give a resultant force of zero.

An equation representing a nuclear change in which the totals of the mass numbers and charge numbers are equal on both sides.

A deformation in which forces make different parts of an object change direction relative to one another, producing a curve or angle.

A high-speed electron emitted from a nucleus during beta-minus decay, represented by $^{0}_{-1}\mathrm{e}$ or $^{0}_{-1}\beta$.