P6 - Waves Flashcards
What is amplitude?
The maximum displacement of a point on a wave, away from it’s undisturbed position.
What is frequency?
The number of waves passing a particular point per second.
What is wave length?
The distance from one point on one wave to the equivalent point on an adjacent wave.
What is wave length measured in?
Lambda
What is a period?
The time it takes for a wave to complete a full cycle.
What is amplitude measured in?
Amps (A)
What is frequency measured in?
Hertz (Hz)
What are the 2 types of waves?
Longitudinal and transverse.
What is a longitudinal wave?
When the oscillations are parallel to the direction of energy transfer.
What is a transverse wave?
The oscillations are perpendicular to the direction of energy transfer.
What is an oscillation?
A vibration about a rest posistion.
What is Echo sounding?
Used to detect objects in deep water and detect water depth.
What is the limit of human hearing?
20,000 Hz (anything above this is called an ultrasound)
How do you measure wave length?
Place a metre ruler perpendicular to the waves shown on the card.
Measure across as many waves as you can.
Divide that length by the total number of waves.
How do you measure wave frequency?
Count the number of waves passing a chosen point over a given time.
Divide the number of counted waves by the given time period.
What is the normal?
An imaginary line drawn perpendicular to the plane.
What is the angle of incidence?
The angle between the incident (incoming ray) and the normal.
What is the angle of reflection?
The angle between the reflected ray (outgoing ray) and the normal.
What is a rule linking the angle of incidence and the angle of reflection?
Angle of incidence = angle of reflection
What is a specular reflection?
When a reflection surface is smooth so, waves are reflected in a single direction.
What is diffuse reflection?
When a reflection surface is rough, scattering occurs, meaning waves are reflected in different directions.
What is refraction?
The change of direction caused by waves changing speeds as they enter a different material.
What happens when a ray enters a more dense material?
It slows and moves towards the normal.
What happens when a ray enters a less dense material?
It speeds up and moves away from the normal.
Give 2 examples of transverse waves.
Electromagnetic waves.
Seismic s-waves.
Give 2 examples of longitudinal waves.
Sound waves.
Seismic p-waves.
What are the two parts of a longitudinal wave called?
Compressions and rarefactions.
What is meant by frequency 200 Hz?
200 waves pass a point per second.
What is wave speed?
The speed at which a wave moves or energy is transferred through a medium.
Meters traveled per second.
What does a wave transfer?
Energy.
What equation do you use to calculate wave speed?
Wave speed = Frequency x wave length
What is wave speed measured in?
m/s
How do sound waves travel though a solid?
The particles in a solid vibrate and transfer kinetic energy through a material.
What is the frequency range of human hearing?
20 Hz - 20 kHz
Give an example use for ultrasound waves?
Medical or industrial imaging.
What natural event produces seismic waves?
Earthquakes - produces both p-waves and s-waves.
What medium can p-waves travel through?
Solids and liquids.
What medium can s-waves travel through?
Only solids.
How does echo-sounding work?
High-frequency sound waves are emitted, reflected and detected.
Time difference between emission and detection (alongside wave speed) are used to calculate distances.
What are the 2 types of seismic waves?
P-waves and S-waves
What is the purpose of the pinna (in the ear)?
Gathers sound waves from the environment and directs them into the ear canal, where they cause the ear to vibrate.
What are the “small bones” names?
Hammer, anvil and the stirrup.
What is the function of the “small bones”?
Transmit vibrations to the cochlea.
What does the cochlea do?
Converts these vibrations into electrical signals.
What does the auditory nerve do?
Transport the electrical signals to the brain.
What seismic wave has a faster wave speed?
P-waves.
How do we know the mantel is solid from the study of seismic waves?
Both P-waves and S-waves can travel through.