OCR GCSE Physics A key terms

The number of turns on one transformer coil compared with the number on the other.

A representative approximate value for ordinary conditions; it is not an exact value that applies in every case.

Sound with a frequency above the range of human hearing; its echoes can be used to locate boundaries inside an object or body.

Acceleration that remains constant, so velocity changes by an equal amount in each equal time interval.

Motion along a circular path at a constant speed.

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

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

A method of proportional reasoning that first finds the value corresponding to one unit and then scales it to the required number of units.

Reducing and eventually removing the force applied to an object during a deformation test.

A nucleus that may undergo radioactive decay because it is not stable.

An energy transfer that does not help achieve the intended purpose of a device or process.

The upward force exerted by a fluid on an object that is partly or completely immersed in it.

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

Energy transferred in the way intended for the device or process.

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

A region containing no matter. Electromagnetic waves can travel through it, unlike mechanical waves such as sound.

A resistor whose resistance can be adjusted to change the current in a circuit.

A quantity with both magnitude and direction, represented by an arrow.

A quantity that has both magnitude and direction.

Speed in a specified direction.

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

Repeated movement back and forth about a rest position.

An image formed where light rays only appear to originate; it cannot be projected onto a screen.

The part of the electromagnetic spectrum that the human eye can detect.

The unit of potential difference, with symbol V; one volt is one joule per coulomb.

A meter connected across a component to measure potential difference.

The amount of three-dimensional space occupied by a gas or its container.