Physics key terms

A diagram in which boxes represent energy stores and labelled arrows represent transfers between them.

A device with primary and secondary coils wound around an iron core that changes an alternating potential difference.

An object that transmits light but scatters it, so objects cannot be seen clearly through it.

The passage of a wave through a material.

A high-voltage cable used to transfer electrical power over long distances.

An object that transmits light so that objects can be seen clearly through it.

A wave in which the vibration is perpendicular to the direction the wave travels.

The overall direction of change in data over a period of time, rather than a single value or short-term fluctuation.

An abnormal mass of cells produced by uncontrolled cell division; a malignant tumour can invade surrounding tissue and spread through the body.

A machine whose blades are turned by flowing steam, causing a shaft to rotate.

One complete loop of wire around a coil.

The rotational effect produced when a force acts at a distance from an axis or pivot.

The ratio between the numbers of turns on two transformer coils, commonly written as $N_p:N_s$.

An approximate, representative value used as a benchmark; individual values can be higher or lower.

A sensor that can track an object's position by sending out ultrasound pulses and detecting their echoes.

Ultrasound is sound with a frequency above 20 kHz, the upper limit of normal human hearing.

Electromagnetic radiation immediately beyond violet in the spectrum, with a shorter wavelength and higher frequency than visible light.

Forces that combine to give a non-zero resultant force.

A nucleus that has not yet undergone radioactive decay.

Acceleration that remains constant, represented by a straight sloping line on a velocity–time graph.

Motion along a circular path at constant speed.

An approximation in which density is taken to have the same value everywhere in the region being considered.

A field with the same strength and direction at every point in the region considered.

A field that has the same strength and direction throughout a region.

Motion at a constant speed in a straight line, so equal distances are travelled in equal time intervals.

Motion at a constant speed in an unchanging direction.

A standard used to express a measurement, such as the second for time or the metre for length.