Waves Flashcards
Transverse waves…
Oscillate perpendicular to the direction of wave travel. E.g. light waves.
Longitudinal waves…
Oscillate parallel to the direction of wave travel. E.g. sound waves.
What is compression (in a longitudinal wave)?
A region of high pressure in a wave, where particles are close together.
What is rarefaction (in a longitudinal wave)?
A region of low pressure in a wave, where particles are far apart.
What do all waves have in common?
The ability to transfer energy, or information, without transferring matter
Mechanical waves…
Require a medium (e.g. air) to travel through; cannot travel through a vacuum.
EM (Electro-magnetic waves)…
Do not require a medium to travel through; can travel through a vacuum.
Amplitude (m) …
The amplitude of a wave is its maximum displacement from its rest position.
Wavelength (m) …
The wavelength of a wave is the distance between a point on one wave to a similar point on the next wave (i.e. from a peak to peak or trough to trough).
Frequency (Hz) …
The frequency of a wave is the number of waves produced by a source each second, or the number of waves that pass a set point each second. The unit of frequency is the hertz (Hz).
Period (s) …
The period of a wave is the time taken for one complete wave to be produced by a source, or pass through a set point.
If the period of a wave is known, how can its frequency be derived?
By applying the formula “frequency = 1 / period”
Peak…
The peak of a wave is the highest point above its rest position.
Trough…
The trough of a wave is the lowest point below its rest position.
What is the Law of Reflection?
The Law of Reflection states that the angle of incidence is always equal to the angle of reflection.
