Physics key terms

The part of the current-carrying conductor within the magnetic field, represented by $L$ and measured in metres (m).

A transparent object that forms an image by refracting light.

A measure of how strongly a lens converges or diverges light, equal to the reciprocal of its focal length in metres.

The principle that an induced current produces a magnetic field opposing the change that caused the current.

A rigid bar that turns about a pivot and transmits the turning effect of an applied force.

A resistor whose resistance changes according to the intensity of light falling on it.

A device that detects when an interrupt card passes through a light beam, allowing time and velocity to be measured without human reaction-time delay.

The amount of light reaching a given area; greater light intensity means brighter illumination at the LDR.

A large electrostatic spark caused by a build-up of charge in storm clouds and a sudden transfer of charge.

A nucleus with relatively few protons and neutrons and therefore a relatively small mass.

Charges of the same type: either both positive or both negative.

The point beyond which force and extension are no longer directly proportional.

A circuit element whose current–potential difference graph is a straight line through the origin, showing a constant ratio of potential difference to current.

A distortion in which extension is directly proportional to the applied force.

A relationship in which force is proportional to extension, producing a straight force–extension graph through the origin.

A relationship represented by a straight line on a graph; equal changes in one variable produce equal changes in the other.

An imaginary straight line extending in the direction in which a force acts.

A line or curve that represents the overall pattern of plotted data rather than joining each point in turn.

The pressure caused by the weight of the liquid column above a point.

The brown conductor in a mains cable that is at an alternating potential difference of about 230 V relative to earth.

Increasing the force applied to an object during a deformation test.

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

A device that converts a varying electrical signal into sound waves.

A substance placed between moving surfaces to reduce friction.

The use of a substance such as oil or grease between moving surfaces to reduce friction.

A material, object or device that produces a magnetic field and can exert magnetic forces.

A small magnet mounted so that it can turn and align with a magnetic field.

The angle that Earth's magnetic field makes with the horizontal at a particular place.