Electromagnetic Waves

• James Clerk Maxwell - father of electromagnetic theory.
• Magnetic Field - the region of space where a magnet is capable of exerting either a repulsive or attractive force on a magnetic material.
• Electromagnetic Wave - is produced by accelerating charged particles or particles oscillating about an equilibrium position, with the electric field and the magnetic field vibrating perpendicularly to each other and the direction of wave propagation.
• EM Waves or EM Radiation - created as a result of vibrations between an electric field and a magnetic field.
• Hertzian Waves - also known as electromagnetic waves.
• Heinrich Hertz (German Scientist) - showed how electromagnetic waves can be generated and detected.
• Electromagnetic Spectrum - electric and magnetic disturbances that radiate from the source.
• Electromagnetic Radiation - also known as electromagnetic waves.
• Visible Spectrum - the band of colors.
• Radio Waves - longest wavelengths and the lowest frequencies; wavelengths range from 1000 meters to .001 m.

  
  

  Used in: RADAR, cooking food, and satellite transmissions.
• Microwaves - with wavelengths less than 30 cm and higher frequency & shorter wavelength. Cell phones and satellites use microwaves between 1 cm & 20 cm for communication.
• Infrared Waves (Heat) - shorter wavelength, from .001 m to 700 nm, and therefore, a higher frequency "below red".

  
  

  Used for: finding people in the dark and on TV remote

  control devices.
• Visible Light - wavelengths range from 700 nm (red light) to 30 nm (violet light) with frequencies higher than infrared waves.

  
  

  ROY G. BV

  red

  orange

  yellow

  green

  blue

  violet
• Ultraviolet Light - wavelengths range from 400 nm to 10 nm; the frequency (and therefore the energy) is high enough for UV rays to penetrate living cells and cause them damage.
• UVC - skin surface.

  • shortest wavelength
  • do not reach the earth
  • harmless (unless in space)
• UVB - epidermis.

  • affects the top layer of skin
  • make your skin tanned
  • redness, burning, skin cancer
• UVA - dermis.

  • longest wavelength
  • do not make you tanned
  • skin aging, DNA damage
• X-Rays (Roentgen Ray) - wavelengths from 10 nm to .001 nm. These rays have enough energy to penetrate deep into tissues and can cause damage to cells; are stopped by dense materials, such as bone.

  
  

  Used: to look at solid structures, such as bones and bridges (for cracks), and for treatment of cancer.
• Gamma Rays - carry the most energy and have the shortest wavelengths, less than one trillion of a meter (10).
• Scintigram - asthmatic person's lungs.