AQA GCSE Physics key terms

A pair of equal-sized forces in opposite directions that two interacting objects exert on each other. The forces act on different objects.

The duration of an energy transfer or of work being done, measured in seconds (s) in the power equations.

All the energy supplied to a device or system.

A device that converts electrical signals into ultrasound waves and returning ultrasound waves into electrical signals.

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.

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

A wave whose oscillations are at right angles to its direction of travel.

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

Sound with a frequency above the upper limit of human hearing, normally 20 kHz.

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

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

Motion at a constant speed in an unchanging direction.

An energy transfer that does not contribute to the device's intended output.

The resultant upward force exerted by a fluid on an immersed object because pressure is greater on its lower surfaces than on its upper surfaces.

An energy transfer that contributes to the intended purpose of a device or process.

The part of the input energy transferred in the way required for the device's intended purpose.

The extent to which an investigation tests the intended effect because other relevant variables have been controlled.

A component whose resistance can be adjusted to control the current and potential difference in a circuit.

A quantity with both a magnitude and a direction.

A drawing in which arrows represent vectors by their direction and scaled length.

A quantity with both a magnitude (size) and a direction.

Speed in a stated direction, measured in metres per second (m/s).

A graph showing how an object's velocity changes with time, with time on the horizontal axis and velocity on the vertical axis.

Callipers with a sliding scale that measure dimensions more precisely than an ordinary ruler.

An image formed where light rays appear to come from when traced backwards; it cannot be projected onto a screen.