EM spec and Light

• EM spectrum is the range of frequencies ordered from longest wavelength and lowest frequency to shortest wavelength and highest frequency
• Examples of Radiowaves= Satellite communication
• Example of Microwaves= Heating food, satellite communication
• Exampled of infared waves= security(airport), Tv remotes
• Exampled of Visible Light=Sunlight, Moonlight (illumination), for our vision
• Examples of UV light=sunlight, tanning beds, checking bank notes, security markings
• Examples of X-rays= medical imaging(of bones and internal structures)
• Exampled of Gamma Rays= Radiotherapy, sterilizing medical equipment
• Dangers of high frequency electromagnetic waves: Can cause cancer, damage to DNA, damage to cells (because they are ionizing), damage to tissues
• Dangers of radiowaves and microwaves= internal heating of body cells
• Dangers of Infared= skin burns
• Damage of Visible Light= None(can cause blindness if too bright)
• Uv light dangers: can cause skin cancer, and damage and mutations to cells
• Dangers of X-rays= Can cause Cancer, Birth defects, damage and mutation of cells
• Dangers of Gamma Rays= Cancer, Mutations, Damage to DNA
• ionizing means to break apart or to remove electrons from atoms which can cause the body to have issues
• All electromagnetic waves:

  • transfer energy as radiation from the source of the waves to an absorber
  • can travel through a vacuum such as in space
  • travel at the same speed through a vacuum or the air
• What are all electromagnetic waves?

  Transverse
• What is EM spec order

  radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays
• what are the EM spec ordered in?

  The electromagnetic spectrum is ordered in terms of increasing frequency and decreasing wavelength.
• What part of the EM spectrum can our eyes detect?

  Visible light
• substances may absorb, transmit, refract and reflect electromagnetic waves differently due to their being different wavelengths
• if a wave changes velocity(speed) can lead to refraction, as waves travel at different speeds in different substances which can lead into a change in direction which is refraction.
• Radio waves can be produced by, or can themselves induce oscillations in electrical circuits.

  When radio waves are absorbed by a conductor, they create an alternating current. This electrical current has the same frequency as the radio waves.

  The conductor could be, for example, an aerial on a radio