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6.2 Electromagnetic Waves, Screenshot 2020-07-01 at 08.46.06 - Coggle…

- - - - Electromagnetic waves form a continuous spectrum over a range of frequencies. This spectrum, groups them into seven basic types, based on their wavelengthand frequency
- - - - 6) The energy tranferred by the waves is transferred to the electrons in the material of the receiver
        
        7) This energy causes the electrons to oscillate and, if the receiver is part of a complete electrical circuit, it generates an alternating current
        8) This current will have the same frequency as the radio waves that generated it
- - - - Microwave source to food
      - Sun emits energy to Earth
  - - - When electrons change orbit (move closer or further from the nucleus)
      - o When electrons move to a higher orbit (moving further from the nucleus)
      -  The atom has absorbed EM radiation
      - o When the electrons falls to a lower orbit(moving closer to the nucleus)
      -  The atoms has emitted EM radiation
      - If an electron gains enough energy, it can leave the atom to form an ion
      - So gamma rays originate from changes in the nucleus of an atom
  - - - UV light, X-rays and gamma can have hazardous effects on human body tissue.
      - The effects depend on the type of radiation and the size of the dose
      - Radiation dose: how much exposure leads to harm for a person
      - o UV–skin ages prematurely, increasing risk of skin cancer  Sun cream prevents over-exposure in summer
      - o X-ray and gamma are ionisation radiation that can cause the mutation of genes– causing cancer
      -  Minimal exposure should be ensured
  - - - Long wavelength, can travel far without losing quality
    - - Can penetrate atmosphere to reach satellites
    - - Transfer thermal energy
    - - Best reflection/scattering in glass (others have either too short/long wavelengths
    - - Radiates the least heat but more energy
    - - Very high in energy, and can penetrate material easily