# GCSE Physics Glossary

Acceleration: Velocity change as measure in metres per second (m/s2)

Alternating current: Electric current that changes its direction every half-cycle

Amplitude: This is the height which a wave (e.g. sound wave) reaches from the zero position.

Angle of incidence: This is the angle which exists between an incident ray and the normal

Angle of reflection: This is the angle which exists between the reflected ray and the normal

Conduction: This is the transfer of energy within matter

Conductor: This is a material which easily transfers energy by means of electron movement

Convection: This is related to energy transfer within gases and liquids

Critical angle: This is the angle of incidence which occurs which light is refracted at 90 degrees to the normal

Direct current: Current that flows in only one direction

Efficiency: A number or a percentage which represents the ratio energy output to energy input

Electric current: The rate at which electric current flows- unit of measurement is amperes, using the symbol A.

Electron: A subatomic particle which is negatively charged

Equilibrium: An object has equilibrium when it is in a state of rest

Force: That which places a push or pull on an object

Frequency: The rate at which a wave passes a particular point every second

Friction: The force which opposes the movement of a surface over another surface

Fuse: A safety device which contains a wire which melts when too much current passes through it

Gravitational Potential Energy (GPE): That energy which can be attributed to an object’s mass due to its height above the ground.

Hooke’s Law: The extension of a spring is directly proportional to the force applied provided the spring’s limit of proportionality is not exceeded

Kinetic energy: The energy generated by a moving object measured in joules

Longitudinal wave: A wave in which the vibrations of same are in parallel to the direction of the energy transfer.

Mass: The amount or quantity of matter evidenced in an object measured in kilograms (kg)

Ohm’s Law: The current passing through a resistor is directly proportional to the voltage across the resistor. V = I x R

Potential Difference: The unit of measurement for potential difference (pd) is the VOLT (V) and is a measurement of the energy transferred by each coloumb of charge that passes through a conductive material.

Power: The unit of measurement for power is the WATT (W)B and represents the mount of energy transferred every second.

Resistance: The unit of measurement for resistance is the OHM () and represents the opposition to the flow of electric current