Waves Flashcards
What can we use waves for?
Transmitting energy and information
What is the direction of travel of the wave the same as?
The direction in which the wave transfers energy
Describe a transverse wave
The oscillation (vibration) of the particles is perpendicular to the direction in which the wave travels
Describe a lonitudinal wave
The oscillation of the particles is parallel to the direction of the wave
Describe electromagnetic waves
- Can travel through a vacuum
- There are no particles moving, they are oscillations in electric and magnetic fields
- Are transverse
Describe mechanical waves
- E.g. waves on springs and sound waves
- Travel through a medium (substance)
- Can be transverse or longitudinal
Describe sound waves
- Vibrations in the air/other media
- These are eventually picked up by your ear, producing the sound
- Longitundial
Aside from transverse and longitundal, what types of waves are there (and are they transverse or longitundinal)?
- Electromagnetic - Transverse
- Mechanical - Either
- Sound - Longitundinal
Do longitudinal waves have an amplitude?
No
What is the amplitude of a wave?
The height of the wave crest or the depth of the wave trough from the position at rest
Greater amplitude = more energy
Defines the loudness of a sound wave (think of amps)
Complete the sentence:
The greater the amplitude of a wave…
…the more energy a wave has
What is the wavelength of a wave?
The distance from one crest to the next, or from one trough to the next
Measured in metres
What is the frequency of a wave?
The number of complete waves passing a set point per second
Measured in hertz (Hz) which is equivalent to per second
What is the wavelength of a longitudinal wave?
The distance from the middle of one compression/rarefaction to the next
(Instead of from one peak/crest/trough)
What is the frequency of a longitudianl wave?
The number of compressions passing a point per second
(As opposed to crests/troughs/peaks. Still complete waves)
What is meant by a plane mirror?
A flat mirror
When drawing a ray diagram, what should you always remember?
To draw the normal!
Where is the normal line drawn?
Perpendicular to the mirror/medium at the point where the incident ray hits the mirror
What does the law of reflection state?
That the angle of incidence is equal to the angle of reflection
What is the angle of incidence/reflection?
The angle between the incident/reflected ray and the normal
I.e. Not the medium/mirror!