P12 - Wave Properties (PAPER 2) Flashcards
What can waves be used for
To transfer energy and information
What are transverse waves
Waves that oscillate perpendicular to the direction of energy transfer of the waves
What are longitudinal waves
Waves that oscillate parallel to the direction of energy transfer of the waves
What type of waves are all electromagnetic waves
transverse waves
What are the two types of waves
- transverse waves
- longitudinal waves
what are mechanical waves and what type of wave are they
- vibrations that pass through a medium
- can be either transverse or longitudinal
What is the amplitude of a wave
the maximum displacement of a point on the wave from its undisturbed position (top of crest or bottom of trough)
What are the highest points and lowest points of a wave called
The peaks (crests) and the troughs
What is the frequency of a wave
the number of waves passing a point per second
What is the wavelength of a wave
the distance from a point on a wave to its equivalent point on the adjacent wave
What is the formula for calculating the time period
period (s) = 1 / frequency (Hz)
What is the period
the total amount of time it takes for a wave to pass a certain point
what is the relationship between the wave speed, the frequency and the wavelength
wave speed (m/s) = frequency (Hz) x wave length (m)
What is reflection
the change of direction of waves so that they return to the medium that they originated from
What is refraction
The change of the direction in which the waves are travelling when they cross a boundary between one medium and another medium
What two things can happen at the boundary of mediums
- transmitted
- absorbed
What are the two angles in reflection called and what is special about them
- angle of incident
- angle of reflection
- they are the same
What are 4 different types of mechanical wave
- Sound waves
- Water waves
- Seismic waves
- Spring waves
In what condition are plane waves crossing boundaries between materials no refracted
When they cross the boundary at normal incidence
When and why does refraction occur
At boundaries between different materials because their speed and wavelengths change
What can happen at boundaries between different materials
The waves can be transmitted or absorbed
What are sound waves
Vibrations that travel through a medium
Where can sound waves not travel
a vacuum
What change occurs when the frequency of a sound wave increases
the pitch of a note increases
What change occurs when the amplitude of a sound wave increases
he loudness of the note increases
Hoe to sound waves activate the brain
sound waves cause the ear drums to vibrate, and these send signals to the brain
Why is human hearing limited
The conversion of sound waves to vibrations of solids only works over a limited frequency range
What range of sound waves are ultrasound waves
sound waves with a frequency > 20kHz
How are distances calculated using ultrasound waves
ultrasound waves reflected at boundaries are timed, and the timings are used to calculate distances
Is an ultrasound scan safer than an x-ray. Why?
Yes since it is non-ionising
What are seismic waves
waves that travel through the Earth
Where are seismic waves produced
in an earthquake at the epicentre
What is the difference between primary and secondary seismic waves
Primary (P) are longitudinal, secondary (S) are transverse
