Wave Characteristics

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Wave Characteristics
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Waves
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Waves

• A disturbance that carries energy through matter
  or space.

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Medium

• The matter through which a wave travels

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Mechanical Waves

• Waves that require a medium in which to travel.

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Longitudinal Waves

• Waves in which the motion of the particles is
  parallel to the motion of the wave as a whole.

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Longitudinal Waves

• Also called a compressional wave

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Electromagnetic Waves

• A wave that travels at the speed of light. It
  travels by oscillating electric and magnetic
  fields.
• 3.0 X 108 m/s

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Transverse Waves

• Waves in which the motion of the particles is
  perpendicular to the motion of the wave as a whole

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Properties of Waves

• Crest
• Trough
• Amplitude

• Wavelength
• Period
• Frequency

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Period

• The time that it takes a complete cycle or wave
  oscillation to occur
• (T)

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Frequency

• The number of cycles or vibration per unit of
  time
• f1/T
• (measure in Hertz (Hz))

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Electromagnetic Spectrum

• All of the frequencies or wavelengths of
  electromagnetic radiation.

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Wave speed is found to be the ratio of wavelength
to the period. Wave speed is found to be the
frequency times wavelength.
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Reflection and Refraction
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Reflection

• The bouncing back of a wave when the wave hits a
  surface

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Normal

• An imaginary line that is perpendicular to the
  surface.

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Angle of Incidence

• The angle of the light rays hitting the surface.
  It is measured from the normal.

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Angle of Reflection

• The angle of the light rays reflecting off the
  surface. It is measured from the normal.

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Diffraction

• A change in the direction of a wave when the wave
  finds an obstacle or an edge, such as on opening

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Refraction

• The bending of a wavefront as the wavefront
  passes between two substances in which the speed
  of the wafe differs.

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Dispersion

• In optics, the process of separating a wave of
  different frequencies into its individual
  component waves.

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Interference

• The combination of two or more waves that results
  in a single wave

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Two type of Interference

• Constructive Interference
• Destructive Interference

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Standing Wave

• A pattern of vibration that simulates a wave that
  is standing still

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Nodes

• A point in a standing wave that maintains zero
  amplitude

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Antinode

• A point in a standing wave, halfway between two
  nodes, it indicates a position of maximum
  intensity.

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Sound
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Sound waves are longitudinal wavesSpeed of
sound346 m/s
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Pitch

• Measure of how high or low a sound is depending
  on the frequency.

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Beat

• The repeating changes in loudness of two sound
  waves that are interfering
• Beatf1-f2

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Doppler Effect

• An observed change in frequency of a wave when
  the source or observer is moving. When objects
  get closer the frequency increases and has the
  distance increases then the frequency decreases.

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Infrasound

• Slow vibrations of frequencies lower than 20 Hz

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Ultrasound

• Any sound wave with frequencies higher than 20000
  Hz

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Intensity of sound is measure in decibels (dB).
Humans can hear from 0dB to 120dB. 120 dB is the
point when the human hear has pain. Damage
starts at 85 dB. 10dB equals twice the loudness.
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Resonance

• A phenomenon that occurs when two objects
  naturally vibrate at the same frequency.

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Natural Frequency

• The frequency which causes a substance to vibrate.

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SONAR

• Sound Navigation and Ranging a system that uses
  acoustic signals and echo returns to determine
  the location of objects or to communicate.