scans

• Wave-particle duality


  Light behaves as both a particle and a wave
• Types of waves


  • Mechanical waves
  • Electromagnetic waves
• Mechanical waves


  • Can only travel in solid, liquid, and gas
• Electromagnetic waves


  • Can travel in solid, liquid, gas, and vacuum
• Light is an electromagnetic wave created by the vibrations of charged particles and has a constant speed of 300 million m/s in vacuum
• Types of wave motion

  • Transverse waves
  • Longitudinal waves
• Transverse wave


  Wave motion is perpendicular to the direction of wave propagation
• Longitudinal wave


  Wave motion is parallel to the direction of wave propagation
• Examples of transverse waves


  • Light
  • Water waves
• Wavelength


  The distance between one crest to the next crest or one trough to the next trough
• Regions of the electromagnetic spectrum

  • Radio waves
  • Microwaves
  • Infrared
  • Visible light
  • Ultraviolet
  • X-rays
  • Gamma rays
• Uses of electromagnetic spectrum regions

  Radio waves and microwaves: Broadcasting, telecommunications

  Infrared: Transmits heat, military uses

  Visible light: Visible to the naked eye

  Ultraviolet: Sensitive to skin, causes sunburn

  1. rays: Imaging the inside of the body

  Gamma rays: Chemotherapy, highly penetrating
• All regions of the electromagnetic spectrum travel at the same speed of 300 million m/s in vacuum
• Wavelength and frequency are inversely proportional
• Specular reflection


  Reflection of light on smooth surfaces
• Diffuse reflection


  Reflection of light on rough surfaces
• The angle of incidence is equal to the angle of reflection
• Object color under white light


  Reflects the color we see, absorbs the other colors
• Object color under colored light


  Reflects the color of the light, absorbs the other colors
• The true color of an object is seen under white light
• Refraction of light


  The bending of light as it passes from one medium to another
• Refraction of light


  Caused by the difference in speed of light between different media
• Difference in speed of light

  Caused by difference in density of the media
• Air


  Molecules are slightly farther apart than in glass
• Glass


  Is a solid, so molecules are closer together
• Reflection


  The bouncing back of light
• Refraction


  The bending of light as it passes through from one medium to another
• Normal line


  • The reference line for the angle of refraction
• Index of refraction (n)

  The ratio of the speed of light in a vacuum to the speed of light in a material
• Calculating index of refraction

  n = C / V, where C is the speed of light in vacuum and V is the speed of light in the material
• Calculating speed of light in material

  V = C / n, where C is the speed of light in vacuum and n is the index of refraction of the material
• Index of refraction values

  • Diamond
  • Glass
  • Water
  • Air
• Index of refraction


  Inversely proportional to speed of light in material
• Light traveling from air to water

  Water has higher index of refraction, so light travels slower in water
• Angle of refraction


  The angle at which light bends when passing from one medium to another
• High index of refraction


  Light bends towards the normal line
• Low index of refraction


  Light bends away from the normal line
• Light passing from air to water

  Angle of refraction is bent away from the normal line
• Higher index of refraction


  Light travels slower
• Higher index of refraction


  Light bent away from normal line