physics waves

Wave

a transfer of energy from one place to another without transferring matter

Energy transfer in waves

energy moves through oscillations while particles stay in the same place overall

Transverse wave

a wave where vibrations are perpendicular to the direction of travel

Examples of transverse waves

light waves and water waves

Longitudinal wave

a wave where vibrations are parallel to the direction of travel

Examples of longitudinal waves

sound waves

Compression

a region in a longitudinal wave where particles are close together

Rarefaction

a region in a longitudinal wave where particles are spread out

Wavelength (λ)

distance between two identical points on a wave such as crest to crest or compression to compression

Frequency (f)

number of waves passing a point each second measured in hertz

Amplitude

maximum displacement of a wave from its rest position

Wave speed (v)

how fast a wave travels measured in metres per second

Time period (T)

time taken for one complete wave

Wavefront

a line joining points on a wave that are in phase

Frequency units

hertz (Hz)

Wavelength units

metres (m)

Wave speed units

metres per second (m/s)

Time period units

seconds (s)

Wave speed equation

wave speed equals frequency multiplied by wavelength

Wave speed formula

v = fλ

Frequency equation

frequency equals one divided by time period

Frequency formula

f = 1 / T

Time period relationship

time period equals one divided by frequency

Wave speed calculation

multiply frequency by wavelength

Rearranging wave equation

wavelength equals wave speed divided by frequency

Reflection

when a wave bounces off a surface

Angle law of reflection

angle of incidence equals angle of reflection

Refraction

when a wave changes direction because its speed changes in a different medium

Cause of refraction

wave speed changes in different substances

Doppler effect

change in observed frequency when the source or observer is moving

Doppler effect towards

frequency increases and wavelength decreases

Doppler effect away

frequency decreases and wavelength increases

Real example of Doppler effect

ambulance siren sounds higher when approaching and lower when moving away

Waves transfer

energy not matter

Wave speed and medium

waves travel at different speeds depending on the material

Sound waves property

require a medium and cannot travel in a vacuum

Light waves property

can travel through a vacuum

Frequency and wavelength relationship

higher frequency means shorter wavelength

Amplitude and energy relationship

larger amplitude means more energy is carried by the wave

Transverse vs longitudinal comparison

transverse waves vibrate perpendicular while longitudinal waves vibrate paralle