The Properties of Waves Flashcards
What is the Amplitude?
The Maximum displacement of a point on the wave from its undisturbed position
Wavelength definition -
Wavelength - the distance from a point on the wave to the equivalent point on the adjacent wave
Frequency definition -
The number of waves passing a fixed point every second
what is the equation that links period and frequency?
Period(s) = 1/ frequency (Hz)
What is the wave speed?
The distance travelled by each wave in a given amount of time
What is the equation that links wave speed, frequency and wavelength?
Wave speed (m/s) = frequency (Hz) x wavelength (m)
What does a bigger amplitude mean?
The more energy the wave carries
At the boundary between two material, light can be one the the 3 things:
- Reflected
- Transmitted ( this includes being Refracted)
- Absorbed
Angle of incident =
angle of reflection
Where are waves reflected
At different boundaries
What are the different ways the waves can be reflected
- Specular reflection
- Diffuse reflection
What is specular reflection
When a wave is reflected in a singular direction by a smooth surface e.g when light is reflected by a mirror you get a clear reflection
what is a diffuse reflection
When a wave is reflected by a rough surface
E.g. a piece of paper and the reflected rays are scattered in lots of directions
Why do diffuse reflection happen
Because the surface is not smooth so the normal is different for each incoming ray, which means the angle of incidence is difference for each ray
What happened when light is reflected by a rough surface
The surface appears matte and you don’t get clear reflection of objects
What is a transverse wave
The oscillations are perpendicular to the direction of energy transfer
Name 4 examples of a transverse wave
- electromagnetic waves
- seismic S-waves
- ripples and waves in water
- light
What is a longitudinal wave
oscillations are parallel to direction of energy transfer
name 3 examples of longitudinal waves
- sound waves
- ultrasound
- seismic P-waves
What are the 2 main types of waves
-Mechanical waves
- Electromagnetic waves
What are mechanical waves
Waves that vibrate through a medium e.g. sound
What are electromagnetic waves
Waves that can travel through a vacuum (no medium is needed) e.g. light
All electromagnetic waves are transverse / longitudinal
Transverse
What are sound waves
Sound waves are vibrations that travel through a medium
How are sound waves caused
- vibrating objects
- vibration are passed to the surrounding medium as a series of compressions and rarefactions
How do you hear sound
- sound waves make your ear drum vibrate
- vibrates passed onto tiny bones in your ear called ossicles, through semicircular canals and to the cochlea
- cochlea turns these vibrations into electrical signals which was sent to the brain
What is the hearing range for a human
20 Hz - 20kHz
What is ultrasound?
Ultrasound are sound waves above the frequency of 20kHz
what are the uses for ultrasound
- pre-natal scanning
- medical uses( skin burns)
- clean jewelry
what happened when ultrasound reaches a boundary
- they are partially reflected so some of the ultrasound waves are reflected at the boundary, and some are transmitted(refracted)
- time taken for the waves to reflect ( leave a source and return to a detector ) is measured
- time it takes to reflect back to the detector can measure thedepth of the boundary
