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Properties of Waves.ppt

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					          Properties of Waves
• Objectives:
  – Identify and describe four wave properties
    (amplitude, wavelength, frequency and wave
    speed)
  – Explain how amplitude and frequency are
    related to the energy of a wave.
The amplitude of a wave is the maximum
 distance the wave vibrates from its rest
 position
The rest position is where the particles of a
 medium stay when there are no
 disturbances.
The larger the amplitude is, the taller the
 wave is
Amplitude is a
measurement of
the distance
particles in the
medium vibrate as
a wave passes
through.
The amplitude of a
sound wave is its
loudness.
A wave with a large amplitude carries more energy than
  a wave with a small amplitude
A wavelength is the distance between any two
 adjacent crests or compressions in a series of
 waves.
The distance between two adjacent troughs or
 rarefactions is also a wavelength.
The wavelength can be measured from any
 point on one wave to the corresponding point
 on the next wave
The wavelength of the 
  wave in the diagram 
  above is given by 
  letter ______.
The amplitude of the 
  wave in the diagram 
  above is given by 
  letter _____.
Indicate the interval which represents one
full wavelength.

          
                                                    

    1.  a to c 
    2.  b to d 
    3.  a to g 
 
    4.  c to g 
The number of waves produced in a given
  amount of time is the frequency of the wave.
You can measure frequency by counting either
  the number of crests or the number of troughs
  that pass a point in a certain amount of time
Frequency is usually expressed in hertz (Hz)
One hertz equals one wave per second
If the amplitudes are equal, high-frequency
  waves carry more energy than low-frequency
  waves
Because frequency and wavelength are so closely
  related, you can relate the amount of energy
  carried by a wave to the wavelength.
A wave with a short wavelength carries more
  energy than a wave with a long wavelength.
• Review:
  – The shorter the wavelength the
    higher the frequency
  – The higher the frequency the
    greater the energy
         Wave Speed
Wave speed is the speed at which a wave
  travels.
Speed is the distance traveled over time, so
  wave speed can be found by measuring
  the distance a single crest or compression
  travels in a given amount of time.
The speed of a wave depends on the
 medium in which the wave is traveling.
For example, the wave speed of sound in
 air is about 340 meters per second, but
 the wave speed of sound in steel is
 about 5,200 meters per second
            Wave equations
Wave speed is equal to the frequency multiplied by
  the wavelength
Wavelength is equal to the wave speed divided by
  the frequency
Frequency is equal to the wave speed divided by
  the wavelength
What is the frequency of a wave if it has a speed of 12
 centimeters per second and a wavelength of 3
 centimeters?

A wave has a frequency of 5 hertz and a wave speed of
  18 meters per second. What is its wavelength?

Did you know that the speed of light is about 300,000,000 
  meters per second.  That is about 880,000 times faster 
  than sound.

				
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posted:2/20/2014
language:English
pages:16
Lingjuan Ma Lingjuan Ma
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