Edexcel GCSE Physics key terms

The mains wire that completes the normal circuit and is at approximately the same potential as Earth.

A neutral particle found in an atomic nucleus; a neutron can be absorbed by U-235 and can also be emitted during fission.

Radiation consisting of neutrons emitted from unstable nuclei.

An extremely dense stellar remnant formed when the collapsed core left by a supernova is not massive enough to become a black hole.

The SI unit of force, with symbol N.

An instrument used to measure force in newtons.

The law stating that when two objects interact, each exerts a force on the other that is equal in magnitude and opposite in direction.

A force that can act between objects without them touching.

A relationship represented by a curve rather than a straight line; the rate at which one variable changes relative to the other is not constant.

A finite energy resource that is not replenished as quickly as it is used and will eventually run out.

An imaginary line drawn at right angles to a boundary where a wave meets it.

A force exerted by a surface on an object in contact with it, acting perpendicular to the surface.

A force acting at right angles to a surface.

The pole of a freely suspended magnet that points approximately towards geographic north, labelled N.

A sequence of nuclear fissions in which neutrons released by one fission cause further nuclei to split.

The positive electric charge of a nucleus, produced by its protons.

An equation using nuclide and particle symbols to represent a change involving an atomic nucleus.

The splitting of a heavy atomic nucleus into two smaller nuclei, releasing energy and usually further neutrons.

A finite material, such as uranium, from which energy can be released and used, principally to generate electricity.

The joining of light atomic nuclei to form a heavier nucleus, releasing energy.

A standard way of representing an isotope using its chemical symbol, mass number and atomic number.

The generation of electricity using energy released by reactions in atomic nuclei.

Radiation emitted by unstable atomic nuclei.

A change involving an atomic nucleus, which can release energy as particles or electromagnetic radiation.

The part of a nuclear power station where a controlled fission chain reaction releases thermal energy.

A change in the arrangement of protons and neutrons within a nucleus, without changing their total numbers.

A proton or neutron in an atomic nucleus.