physics unit 1 waves Flashcards
what is the speed of sound in air
330m/s
what is the speed of em waves in a vacuum/air
3 times 10 to the power of 8 m/s
what is frequency, the equation and what is it measured in
frequency is the number of vibrations also known as oscillations per second.
frequency= 1 divided by period.
it is measured in hertz.
it could also be frequency= oscillations divided by time
what is the periodic time of a wave, the equation and what is it measured in.
the periodic time of a wave is the time taken to complete one vibration.
the equation is periodic time= 1 divided by frequency.
it is measured in seconds.
what is amplitude
the distance from the rest position of a wave to the top of a waves peak
what is the wavelength
the distance between two adjacent wavefronts
what does a displacement time graph show
focuses attention on oscillations at just one point in space
what does displacement distance graph show
shows you the wave shape over the whole space at that instant
how can phase be expressed
as fractions of a cycle or as an angle or as multiple of wavelengths
what does phase of a wave mean
it means how far through a cycle the wave is
what is phase difference
measure of the difference in where two waves are in their cycle
a full cycle corresponds to multiples of what angle
2π which is 360 degrees
what does half cycle correspond to
180 degrees which is π rad
wavelength and frequency
mediums, how many cycles does one wavelength take
in a given medium, waves travel at a fixed speed or velocity. and travelling a one wavelegnth takes one cycle which is one periodic time.
musical instruments with strings
how can the notes be tuned
by changing the medium( the string) which changes the speed of the waves.
what do thicker strings with more mass per unit length produce
they give a slower speed and hence a lower note
what do tighther strings with more tension produce (T)
faster speed so a higher note. tension is measured in newtons because it is a force.
air columns in pipes
how can you tune brass or woodwind instruments
by changing the length of pipe being used because the speed of sound is fixed in temperature and pressure
speed of light
what is the speed of light in a vacuum
2.998 times 10 to the power of 8 ms to the power of negative 1.
it is represented by the letter c. nothing is faster than c ( the speed of light)
does light move faster or slower in a solid or liquid media
slower speed and is shown by the letter v
transverse waves
three properties of em waves
- they are all transverse waves
- and travel at the same speed which is the speed of light in a vacuum
- energy carried in the waves vary
two things for a wave to be in phase
if two points on a wave have the same displacement and direction of vibration
two things for a wave to be in anti-phase
if two points have the same magnitude of displacement but different direction of vibration (opposite)
