P5.1 Flashcards
What is a wave?
A regular disturbance that transfers energy in the direction the wave is travelling without transferring matter.
What are the two types of waves?
- Transverse
- Longitudinal
What is a transverse wave?
A wave for which the oscillations are perpendicular to the direction of energy transfer.
What is a longitudinal wave?
A wave for which the oscillations are parallel to the direction of energy transfer.
Give two examples of transverse waves.
Electromagnetic waves
Seismic s-waves
Give two examples of longitudinal waves
Sound waves
Seismic p-waves
What are the two parts of a longitudinal wave called?
Compressions and rarefactions
What is a wave’s amplitude?
The maximum displacement of a point on a wave from its undisturbed position.
What is wavelength?
The distance from a point on a wave to the same position on the adjacent wave. Most commonly peak to peak or trough to trough.
What is the frequency of a wave?
The number of waves that pass a given point each second.
What is the unit used for frequency?
Hertz, Hz
What is meant by a frequency of 200Hz?
200 waves pass a given point each second
What is wave speed?
The speed at which energy is transferred through a medium.
What does a wave transfer?
Energy
State the equation used to calculate wave speed. Give appropriate units.
Wave speed= Frequency x Wavelength.
Speed (m/s), Frequency (Hz), Wavelength (m)
What word is used to describe when a wave bounces off a surface?
Reflection
What is refraction?
Refraction is the change in speed of a wave as it reaches a boundary between two media, resulting in a change in direction.
What property of wave is not changed by refraction?
The frequency.
When entering a denser material, light waves…
… slow down and bend towards the normal.
What is a ripple tank?
A shallow glass tank with an oscillating paddle/needle to create waves. It is illuminated from above so the waves can be seen on the surface below the tank.
Describe how to demonstrate reflection using a ripple tank.
Waves will reflect off the glass sides of the tank.
How do sound waves travel through a solid?
The particles in the solid vibrate and transfer kinetic energy through the material.
How does the human ear work?
- The outer ear collects the sound which travels into the ear.
- The sound waves cause the eardrum to vibrate at the same frequency.
- This is amplified by three ossicles (small bones)
- This causes the hair in the cochlea to vibrate.
- The cochlea converts the vibrations into electrical signals.
- The signals are passed to brain through the auditory nerve.
- The brain converts the electrical signals into sound.
What is the frequency range of human hearing?
20 Hz - 20kHz
(1kHz = 1000 Hz)
What are ultrasound waves?
Waves which have a frequency higher than the upper limit of human hearing.
Give an example use for ultrasound waves.
Medical or industrial imaging.
