Electromagnetic%20Waves

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Electromagnetic Waves

• Section 1 What are electromagnetic waves?
• A. Electromagnetic waves are made by vibrating
  electric charges and can travel through space.
• B. Electric and magnetic fieldsrelated forces
  that operate even in empty space
• 1. A moving electric charge creates a magnetic
  field.
• 2. Changing magnetic fields create changing
  electric fields and vice versa.

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Electromagnetic Waves

• C. Electromagnetic waves are produced when an
  electric charge is vibrating.

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Electromagnetic Waves

• D. Properties of electromagnetic fieldscarry
  radiant energy
• 1. Frequency and wavelengthas frequency
  increases, wavelength decreases
• a. Frequency is the number of vibrations per
  second measured in hertz.
• b. Wavelength is the distance from one crest to
  another and is measured in meters.
• 2. Wave speedin the vacuum of space, 300,000
  km/s electromagnetic waves slow as they travel
  through matter.

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Electromagnetic Waves

• E. Waves and particles difference not clear
• 1. Light can behave as a particle, a photon,
  whose energy depends on frequency.
• 2. All particles can behave like a wave

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Electromagnetic Waves

• Section 2 The Electromagnetic Spectrum
• A. The entire range of electromagnetic wave
  frequencies is called the electromagnetic
  spectrum.

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Electromagnetic Waves

• B. Radio waveslow-frequency electromagnetic
  waves with wavelengths from less than a
  centimeter to about 1000 meters
• 1. Microwavesradio wave lengths of about 1 to 10
  cm
• 2. Radarradio waves bounced off an object to
  determine its speed and location
• 3. Magnetic Resonance Imaging (MRI)radio waves
  produce an image of the inside of the body

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Electromagnetic Waves

• C. Infrared waveselectromagnetic wave with a
  slightly higher frequency than radio waves
  people feel it as thermal energy or warmth
• D. Visible lighthas wavelengths between about
  390 to 770 billionth of a meter can be seen with
  the eye

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Electromagnetic Waves

• E. Ultraviolet waveshave frequencies slightly
  higher than visible light can damage skin
• 1. Ultraviolet light can kill bacteria.
• 2. Ultraviolet light can be absorbed by some
  fluorescent materials and released as visible
  light.
• 3. Ozone layer above Earths surface absorbs most
  of the Suns harmful ultraviolet waves.

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Electromagnetic Waves

• F. X rays and gamma raysultra-high-frequency
  electromagnetic waves that can travel through
  matter, break molecular bonds, and damage cells
• 1. X rays are used to provide images of bones and
  to examine suitcases at airports without opening
  them.
• 2. Radiation therapy is used to kill diseased
  cells.

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