Waves Flashcards
What two ways can wave be found?
Transverse or longitudal
If a wave is transfers what does it mean?
It means the oscillations are perpendicular to the direction of the energy transfer
What does it mean if the wave is longitudinal?
It mean sthe oscillations are parallel to the direction of energy transfer
What type of wave are electromagnetic waves?
Transverse
What type of waves are sound waves?
Longitudinal and they cause vibrations in a medium, which are detected as sound
What type of waves are mechanical waves?
Transverse or longitudinal
What speed do all electromagnetic waves travel at in a vacuum?
The same speed
What do electromagnetic waves form?
A continuous spectrum
What do waves transfer?
Energy
What do longitudinal waves show?
Areas of compression and rarefaction
Waves can be….
Reflected, refracted and detracted
When do waves under go a change in direction?
When they are refracted at an interface
What is the angle of incidence equal to?
The angle of reflection
An image is produced in a plain mirror is…
Virtual
What is the pitch of a sound determined by?
It’s frequency and loudness by it amplitude
What is the Doppler effect?
If a wave source (could be light, sound or microwave) is moving relative there will be a change in the observed wavelength and the frequency.
When the source moves away from the observer, the observed wavelength increases and the frequency decreases. The opposite will happen when the source moves towards the observer.
There is an observed increase in the … of light from most distant galaxies
Wavelength
What is red-shift?
The further away the galaxies are the fast they are moving and the bigger the observed increase in wavelength
What is cosmic microwave background radiation (CMBR)?
It is a form of electromagnetic radiation filling the universe. It comes from radiation that was present shortly after the beginning of the universe
What can the Big Bang theory explain?
The existence of CMBR
How does the observed red-shift provide evidence that the universe is expanding and that it support the Big Bang theory?
Astronomers have found that the further from us a star is the more its light is red shifted. This tells us that distant galaxies are moving away from us, and that the further a galaxy is the faster it is moving away. Since we cannot assume that we have a special place in the universe this is evidence for a generally expanding universe. It suggests that everything is moving away from everything else. The Big Bang theory says that this expansion started billions of years ago with an explosion.
What do waves do?
They transfer energy
What is frequency?
The frequency of a wave is the number of waves produced by a source each second. It is also the number of waves that pass a certain point each second.
The unit of frequency is the hertz (Hz).
What is amplitude?
The amplitude of a wave is its maximum disturbance from its undisturbed position. Take care, the amplitude is not the distance between the top and bottom of a wave.
What is the wavelength?
The wavelength of a wave is the distance between a point on one wave and the same point on the next wave. It is often easiest to measure this from the crest of one wave to the crest of the next wave.
What is the normal?
It is a construction line perpendicular to the reflecting surface at the point of incidence
What are sound waves and what do they cause?
They are longitudinal
They cause vibrations in a medium, which are detected as sound
What are echos?
Then sounds reflect of a hard surface
