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An Introduction An Introduction to Wavesto Waves
3U Physics3U Physics
What is a wave?What is a wave?
A A wavewave is a disturbance which carries is a disturbance which carries energy from one location to another.energy from one location to another.
What is a wave?What is a wave?
A A wavewave is a disturbance which carries is a disturbance which carries energy from one location to another.energy from one location to another.
The material the disturbance travels The material the disturbance travels through is the through is the ??
The movement of the disturbance is The movement of the disturbance is referred to as referred to as ??
What is a wave?What is a wave?
A A wavewave is a disturbance which carries is a disturbance which carries energy from one location to another.energy from one location to another.
The material the disturbance travels The material the disturbance travels through is the through is the mediummedium..
The movement of the disturbance is The movement of the disturbance is referred to as referred to as ??
What is a wave?What is a wave?
A A wavewave is a disturbance which carries is a disturbance which carries energy from one location to another.energy from one location to another.
The material the disturbance travels The material the disturbance travels through is the through is the mediummedium..
The movement of the disturbance is The movement of the disturbance is referred to as referred to as propagationpropagation..
2 Types of Waves2 Types of Waves
A A longitudinal wavelongitudinal wave is a wave in which is a wave in which the particles of the medium move in a the particles of the medium move in a direction parallel to the direction of direction parallel to the direction of propagation.propagation.
2 Types of Waves2 Types of Waves
A A longitudinal wavelongitudinal wave is a wave in which is a wave in which the particles of the medium move in a the particles of the medium move in a direction parallel to the direction of direction parallel to the direction of propagation.propagation.
2 Types of Waves2 Types of WavesA longitudinal wave is also called a A longitudinal wave is also called a
pressure wavepressure wave or a or a sound wavesound wave..
2 Types of Waves2 Types of WavesA longitudinal wave is also called a A longitudinal wave is also called a
pressure wavepressure wave or a or a sound wavesound wave..
The regions of increased The regions of increased pressure/density are called pressure/density are called ??..
The regions of decreased The regions of decreased pressure/density are called pressure/density are called ??..
2 Types of Waves2 Types of WavesA longitudinal wave is also called a A longitudinal wave is also called a
pressure wavepressure wave or a or a sound wavesound wave..
The regions of increased The regions of increased pressure/density are called pressure/density are called compressionscompressions..
The regions of decreased The regions of decreased pressure/density are called pressure/density are called ??..
2 Types of Waves2 Types of WavesA longitudinal wave is also called a A longitudinal wave is also called a
pressure wavepressure wave or a or a sound wavesound wave..
The regions of increased The regions of increased pressure/density are called pressure/density are called compressionscompressions..
The regions of decreased The regions of decreased pressure/density are called pressure/density are called rarefactionsrarefactions..
2 Types of Waves2 Types of Waves
A A transverse wavetransverse wave is a wave in which the is a wave in which the particles of the medium move in a direction particles of the medium move in a direction perpendicular to the direction of perpendicular to the direction of propagation.propagation.
Although sound waves are not transverse Although sound waves are not transverse waves, we often represent them as waves, we often represent them as transverse waves because transverse waves transverse waves because transverse waves are easier to draw.are easier to draw.
2 Types of Waves2 Types of Waves
The vertical axis represents not The vertical axis represents not displacement but pressure.displacement but pressure.
Snapshot of a Transverse Snapshot of a Transverse WaveWave
The dashed line represents the equilibrium The dashed line represents the equilibrium position of the particles.position of the particles.
Snapshot of a Transverse Snapshot of a Transverse WaveWave
The positions of maximum displacement are The positions of maximum displacement are referred to as referred to as crestscrests (positive displacement) (positive displacement) and and troughstroughs (negative). (negative).
The maximum displacement is the The maximum displacement is the amplitudeamplitude..
Snapshot of a Transverse Snapshot of a Transverse WaveWave
The positions of maximum displacement are The positions of maximum displacement are referred to as referred to as crestscrests (positive displacement) (positive displacement) and and troughstroughs (negative). (negative).
The maximum displacement is the The maximum displacement is the amplitudeamplitude..
Amplitude = EnergyAmplitude = Energy
Snapshot of a Transverse Snapshot of a Transverse WaveWave
The distance between one crest and the The distance between one crest and the next crest (or one trough and the next next crest (or one trough and the next trough) is thetrough) is the
Snapshot of a Transverse Snapshot of a Transverse WaveWave
The distance between one crest and the The distance between one crest and the next crest (or one trough and the next next crest (or one trough and the next trough) is the trough) is the wavelengthwavelength, represented , represented byby
Snapshot of a Transverse Snapshot of a Transverse WaveWave
The distance between one crest and the The distance between one crest and the next crest (or one trough and the next next crest (or one trough and the next trough) is the trough) is the wavelengthwavelength, represented , represented by by ..
Snapshot of a Transverse Snapshot of a Transverse WaveWave
The time it takes one complete wavelength The time it takes one complete wavelength to pass a single point is theto pass a single point is the
Snapshot of a Transverse Snapshot of a Transverse WaveWave
The time it takes one complete wavelength The time it takes one complete wavelength to pass a single point is the to pass a single point is the periodperiod, , represented byrepresented by
Snapshot of a Transverse Snapshot of a Transverse WaveWave
The time it takes one complete wavelength The time it takes one complete wavelength to pass a single point is the to pass a single point is the periodperiod, , represented by represented by TT..
Snapshot of a Transverse Snapshot of a Transverse WaveWave
cyclesof
tT
#
The time it takes one complete wavelength The time it takes one complete wavelength to pass a single point is the to pass a single point is the periodperiod, , represented by represented by TT..
Snapshot of a Transverse Snapshot of a Transverse WaveWave
The number of complete wavelengths that The number of complete wavelengths that pass a single point in one second is the pass a single point in one second is the frequencyfrequency, represented by , represented by ff..
fTor T
f 1 1
FrequencyFrequency
Frequency is measured in units of Frequency is measured in units of 1/s or s1/s or s-1-1
or Hertz (Hz).or Hertz (Hz).
“I do not think that the wireless waves I have discovered will have any practical application.”
Wave SpeedWave Speed
The speed of a wave is therefore:The speed of a wave is therefore:
vd
t
Wave SpeedWave Speed
The speed of a wave is therefore:The speed of a wave is therefore:
vd
t T
Wave SpeedWave Speed
The speed of a wave is therefore:The speed of a wave is therefore:
vd
t Tf
Wave SpeedWave Speed
The speed of a wave is therefore:The speed of a wave is therefore:
The speed of a sound wave in air at room The speed of a sound wave in air at room temperature (20temperature (20ooC) is 344 m/s.C) is 344 m/s.
vd
t Tf
Sound Wave ExampleSound Wave Example
Calculate the wavelength of the sound Calculate the wavelength of the sound wave produced by a 125 Hz tuning wave produced by a 125 Hz tuning fork in air at 20fork in air at 20ooC.C.
Sound Wave ExampleSound Wave Example
Calculate the wavelength of the sound Calculate the wavelength of the sound wave produced by a 125 Hz tuning wave produced by a 125 Hz tuning fork in air at 20fork in air at 20ooC.C.
?
125
344
Hzf
v sm
Sound Wave ExampleSound Wave Example
Calculate the wavelength of the sound Calculate the wavelength of the sound wave produced by a 125 Hz tuning wave produced by a 125 Hz tuning fork in air at 20fork in air at 20ooC.C.
?
125
344
Hzf
v sm
mHz
f
vfv
sm
75.2125
344
More PracticeMore Practice
Inquiry Activity: Slinky WavesInquiry Activity: Slinky Waves
Homework: An Introduction to WavesHomework: An Introduction to Waves
