Physics key terms

A force acting at right angles to a surface.

The end of a magnet or compass needle that points towards north when free to turn.

A temperature-sensitive resistor whose resistance falls as its temperature rises.

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 energy store associated with the arrangement and interactions of particles within an atomic nucleus.

An equation that represents a change in an atomic nucleus, with mass numbers and atomic numbers balanced on both sides.

The splitting of a large, unstable atomic nucleus into two smaller nuclei, with the release of neutrons, gamma rays and energy.

Material used in nuclear reactions to release energy; fuels such as uranium are finite and therefore non-renewable.

A process in which light atomic nuclei join to form heavier nuclei, releasing energy.

A model in which an atom has a tiny, positively charged central nucleus surrounded by electrons, with most of the atom being empty space.

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 compact representation of a nucleus showing its element symbol, mass number and atomic number, written $^{A}_{Z}\mathrm{X}$.

A proton or neutron in an atomic nucleus.

The small, dense central part of an atom, containing protons and usually neutrons; a hydrogen-1 nucleus contains only one proton.

A particular type of nucleus specified by its numbers of protons and neutrons.

A notation of the form $^{A}_{Z}X$, where $X$ is the element symbol, $A$ is the mass number and $Z$ is the atomic number.

The number of complete loops of wire in a transformer coil.

A person or device that receives an electromagnetic wave.

The unit of resistance, with symbol Ω.

A conductor for which current is directly proportional to potential difference when its temperature is constant.

A material that does not transmit light through it.