Electromagnetic waves

• ELECTROMAGNETIC WAVES


  Are transverse waves with a wide range of properties and uses.

  Some waves are hazardous to human body tissues
• Electromagnetic waves


  are created as a result of vibrations between an electric field and a magnetic field.

  
  

  _______ travel at 300,000,000 meters per second (m/s) (3.0x108 m/s)through a vacuum.
• ELECTROMAGNETIC WAVES


  1. Transfer energy from the source of the waves to an absorber.

  
  

  2. Can travel through a vacuum such as in space.

  
  

  3. All travel at the same velocity through a vacuum
• ELECTROMAGNETIC WAVES


  form a continuous spectrum of waves
• short


  waves with a very _____ wavelength, high frequency and high energy
• long


  waves with a very ______ wavelength, low frequency and low energy
• Red


  light has the lowest frequencies of visible light
• Violet


  light has the highest frequencies of visible light
• visible light


  All electromagnetic waves are light, but the band of the electromagnetic spectrum that people and animals can see is called
• FREQUENCY


  The number of crests that pass a given point within one second is described as the frequency of the wave.
• Hertz(Hz)


  One wave one cycle per second is called a
• Heinrich Rudolf Hertz


  the unit of frequency is named after him.
• Wavelength


  The distance between crests is the
• electron volts(eV)


  An electromagnetic wave can also be described in terms of its energy in units of measure called
• Thomas Young


  1803, ________ presented his experimental results on the nature of light
• Jame Clerk Maxwell


  In 1873, a Scottish physicist named ________ published a theory that accounted for the physical origins of light
• electromagnetism


  Maxwell's work synthesized these two ideas, ELECTRICTY and MAGNETISM which had previously been considered separate phenomena. His new theory was aptly named a theory of
• Jame Clerk Maxwell


  One prediction that came from ______ equations was that a charge moving back and forth in a periodic fashion would create an oscillating electric field
• permittivity and permeability


  Maxwell's calculation of the speed of an electromagnetic wave included two important constants: the ______ of free space
• Permittivity


  is also known as the electric constant, the strength of electrical force between two charged particles in a vacuum.
• Permeability


  is a magnetic analogue of the electric constant. It describe the strength of the magnetic force on an object in a magnetic field.
• Albert Michelson


  Polish-American physicist _______ made a very precise measurement of the speed of light that was extremely close agreement with Maxwell's predicted value. 299,798 km/sec (speed of light)

  This led maxwell to realized that light was an electromagnetic wave and part of electromagnetic spectrum
• TOTAL INTERNAL REFLECTION


  A light wave does not just stop when it reaches the end of the medium.

  
  

  is a phenomenon that occurs at the boundary between two mediums, such that if the incident angle in the first medium is greater than the critical angle, then all the light is reflected back into that medium.

  
  

  Light waves undergoes certain behaviors like reflection, transmission/refraction, and diffraction
• Reflection


  of a light wave involves the bouncing of a light wave off the boundary
• law of reflection


  The fundamental law that governs the reflection of light is called the ______
• law of reflection


  states that When a light ray reflects off a surface, the angle of incidence is equal to the angle of reflection.
• Refraction


  of a light wave involves the bending of the path of a light wave upon crossing a boundary and entering a new medium
• Snell's Law


  The fundamental law that governs the refraction of light is ______
• Snell's law


  states that When a light ray is transmitted into a new medium, the relationship between the angle of incidence (Oi) and the angle of refraction (Or)
• Polarizer


  is an optical filter that lets light waves of a specific polarization pass through while blocking light waves of other polarizations.
• Polarizers


  are usually made out of oblong shaped molecules, all aligned in the same direction
• Polarization (Malus's law)


  This law states that when a totally planed-polarized light is incident on the analyzer, the intensity (I) of the light transmitted by the analyzer is directly proportional to the square of the cosine of the angle between the analyzer's transmission axis and the polarizer