Physics: Waves: Key terms

Transverse

Transverse

a wave in which the oscillations are at right-angles to the direction of energy transfer, e.g. water waves

Longitudinal

a wave in which the oscillations are parallel to the direction of energy transfer, e.g. sound waves

Oscillate

to vibrate / swing from side to side with a regular frequency

Frequency

the number of times that a wave / vibration repeats itself in a specified time period

Amplitude

the maximum displacement that any particle in a wave achieves from its undisturbed position, measured in metres (m)

Wavelength

the distance from one point on a wave to the equivalent point on the next wave, measured in metres (m), represented by the symbol l

Period

the time taken for a wave to complete one oscillation; the time it takes for a particle in the wave to move backwards and forwards once around its undisturbed position

Electromagnetic (EM) waves

a continuous spectrum of waves formed by electric and magnetic fields, ranging from high frequency gamma rays to low frequency radio waves

Absorbed

to take in and retain (all or some) incident radiated energy

Transmitted

when waves are sent out from a source or pass through a material

Reflected

when a wave meets a boundary between two different materials and is bounced back

Refracted

when a wave meets a boundary between two different materials and changes direction

Refractive index

a measure of the extent to which light is refracted by a material

Medium

a material or substance

Normal

at right-angles to / perpendicular to

Microwaves

electromagnetic radiation in the wavelength range 0.3 to 0.001 metres, used in satellite communication and cooking

Infared

the part of the electromagnetic spectrum with a longer wavelength than light but a shorter wavelength than radio waves

Ultraviolet

the part of the electromagnetic spectrum with wavelengths shorter than light but longer than X-rays

X-rays

the part of the electromagnetic spectrum with wavelengths shorter than that of ultraviolet radiation but longer than gamma rays

Gamma rays

high frequency, short wavelength electromagnetic waves; a type of nuclear radiation, emitted from a nucleus

Ionising

refers to radiation that can cause atoms to lose or gain atoms, becoming ions