13 of the Physics glossary’s terms, each with the part of the syllabus where you first meet it.
The time taken for the number of undecayed nuclei of a nuclide, and so the activity of a sample, to fall to half its initial value.
One of the standing waves a system can support; the nth harmonic has a frequency n times that of the first harmonic.
The energy needed to raise the temperature of a particular object by 1 K, equal to ; measured in .
A device that runs a cycle, taking thermal energy from a hot reservoir, converting part of it to work and rejecting the rest to a cold reservoir.
A device that transfers energy from the hot primary coolant to water in a separate loop, turning it into steam, without the two fluids mixing.
A device that uses work to transfer thermal energy from a cold reservoir to a hot one, used to heat buildings.
A graph of temperature against time for a substance heated at constant power: sloping sections where one phase warms, flat sections where the phase changes.
A resistor, usually of high-resistivity wire such as nichrome, designed to transfer electrical energy to its surroundings as thermal energy.
Damping greater than critical: the system does not oscillate and returns to equilibrium more slowly than with critical damping.
A graph of stellar luminosity (vertical, log scale) against surface temperature (horizontal, log scale, decreasing to the right), on which stars fall into groups such as the main sequence, giants and white dwarfs.
An equation in which every term has the same units; any physically correct equation is homogeneous.
The elastic restoring force of a spring is proportional to its extension and opposite in direction, , up to the limit of proportionality.
A testable statement of the expected relationship between variables, with a scientific reason for expecting it.