Edexcel GCSE Physics key terms

An image made by detecting infrared radiation emitted by objects, allowing differences in temperature to be shown.

The use of materials or structures that reduce the rate of energy transfer by heating.

A material that reduces the rate of thermal energy transfer because it has a low thermal conductivity.

Electromagnetic waves emitted by a body because of its temperature.

A temperature-sensitive resistor. For the negative temperature coefficient thermistors studied here, resistance decreases as temperature increases.

The distance travelled while the driver reacts to a hazard and begins to apply the brakes.

A simplified model in which all refraction is represented as occurring at one line through the lens.

A pair of equal and opposite forces produced by one interaction and acting on two different objects.

The duration for which the wave travels, measured in seconds (s).

The difference between the times at which the same signal reaches two detectors.

The duration over which an energy transfer takes place; in the power equation it is measured in seconds (s).

Harm to cells which can impair or destroy them and, if sufficiently widespread, damage tissue.

Fine powder used to form the printed image in a photocopier or laser printer.

All the energy transferred into a device.

The amount of energy used by a population over a stated period, often one year.

The complete reflection of light at a boundary when it travels towards a lower-refractive-index material at an angle of incidence greater than the critical angle.

The complete pressure measured relative to a vacuum; for an open liquid, it includes atmospheric pressure and the pressure due to the liquid.

A device that converts an electrical signal into ultrasound and returning ultrasound echoes into electrical signals.

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

A device that changes the size of an alternating voltage using two coils linked by a changing magnetic field.

The passage of an electromagnetic wave through a substance.

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

A wave in which the oscillations are perpendicular to the direction in which the wave travels.

A general direction of change shown by data over time, such as a rise or fall.

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.

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