P12 - Wave Properties 2️⃣✅ Flashcards
What is a wave?
Something that transfers energy from one place to another without transferring matter
What is an oscillation?
Vibrations - things moving back and forth in a fixed position
What is a medium?
A substance in which a wave is travelling through e.g. gas, liquid, solid
What are longitudinal waves?
Waves where its oscillations are parallel to the direction in which the wave transfers energy
What are transverse waves?
Waves where its oscillations are perpendicular to the direction in which the wave transfers energy
What is wavelength?
The distance along a wave from one place on one wave to the same place on another
What is amplitude?
The distance from the middle of the wave to the trough or peak
What are mechanical waves?
Waves that travel through a substance (medium)
What are electromagnetic waves?
Waves that travel through a vacuum and therefore no medium is required
Give some examples of mechanical waves
water waves, seismic waves, sound waves (use particles)
Give some examples of longitudinal waves
Sound waves, seismic P waves
Give some examples of transverse waves
electromagnetic waves, seismic S waves, water waves
What is the time period?
The time taken for a wave to pass a point
What is time period measured in?
Seconds
What is frequency?
The number of waves per second
What is the unit of frequency?
Hertz, Hz
How many Hz are in a MHz?
1 Million
How do you get from MHz to Hz?
x 1000000
What is the equation that link wave speed, frequency and wavelength?
wave speed = frequency x wavelength
v = f x λ
m/s Hz m
What is a reflection?
The change of direction of a light ray or wave at a boundary when the ray/ wave stays in the medium
What is a refraction?
A change of direction of a wave caused by a change in speed of a wave when it enters a new medium
What are the 3 things waves can do when they meet a medium?
Be absorbed, reflect or transmit (travel through)
What is pitch?
How high the note is e.g. how high the frequency is
What is loudness?
An everyday word to reference the amplitude of a sound wave
How do you work out a question asking you to work out the depth of the ocean using a sound wave?
You would do d = s x t with your given values and then divide it by two because the depth (distance) would be one stretch of the wave not 2 (the wave would have gone down and hit the bottom (1) and then come back up (2) so we divide by two to get the initial value & depth (1).
What is an ultrasound?
Vibrations at a higher frequency than the human ear can detect.
Why are ultrasounds used when monitoring babes opposed to x-rays?
Because x-rays give off ionising radiation which can be damaging to a developing foetus so they arent used. Ultrasounds do not give off ionising radiation so are much safer to use.
List 4 qualities of a P wave
they travel the fastest
they are called the primary wave as they arrive first
they are longitudinal so travel parallel
they can pass through any state/ medium without difficulty
List 4 qualities of an S wave
they are slower than P waves
they are called secondary waves as they arrive second
they are transverse waves so travel perpendicular
they need a ridged material to propagate through
Why cant S waves travel through the outer core?
Because its a liquid and S waves require a ridged material to propagate through (a solid) so a liquid wont work
Name the 4 main layers of the Earth and give their states
Crust - solid
Mantle - solid
Outer core - liquid
Inner core - Solid
Label the layers of the earth and each layers state
What wave type does this example correlate to?
Transverse waves are often demonstrated by moving a rope rapidly up and down. (oscilations perpendicular)
What wave type does this example correlate to?
Longitudinal waves are often demonstrated by pushing and pulling a stretched slinky spring. (oscilations parallel)
What type of wave is this?
Longituidnal (oscilations parallel) - the waves oscillate through a series of compressions and refractions
Where is the wavelength on this wave?
Where are the compressions on this wave?
What type of wave is this?
Transverse - oscilations go up and down (perpendicular)
Where is the amplitude on this wave?
Where is the wavelength on this wave?
What is the range of normal human hearing?
20Hz to 20000Hz
The closer packed particles are the ________ sound travels
The closer packed particles are the faster sound travels
Sound requires ____________ in order to transmit waves
Sound requires particles in order to transmit waves
Wavelength gets ________ as sound speeds up in ____________ density materials
Wavelength gets longer as sound speeds up in high density materials
Frequency of sound waves ________________
Frequency of sound waves always remians the same
Wavelength gets ____________ as sound slows down in ________ density materials
Wavelength gets shorter as sound slows down in low density materials
How do human ears work?
- Sound waves go down ear canal and hit ear drum
- They then cause the ear drum to vibrate
- Which sends vibrations along tiny bones and through semi-circular canals until it reaches cochlea
- cochlea converts vibrations into electrical signals which are sent down auditory neve to brain where it inteprets them as sounds
What is a signal generator?
A device used to change the frequency of vibrations across a wave/ string
