HDKSHEHRJ

• RADIO WAVES are made by OSCILLATING CHARGED

  • when radio waves are absorbed they create an alternating current, AC, @ same frequency as the radio wave
  • you can produce radio waves w/ AC_ the object which charges oscillate to create radio waves is called a TRANSMITTER
  • when transmitted radio waves reach a RECIEVER, it’s ABSORBED; energy carried by wave is TRANSFERRED to ELECTRONS of the RECEIVER
  • this generates AC because it makes charges oscillate
• RADIO WAVES USES

  • LONG-WAVE RADIO (1-10km) DIFFRACT around earth; receiver can get even if it’s NOT in line of the sight of transmitter
• RADIO WAVES USES

  • SHORT WAVE RADIO SIGNALS (10m-100m) can be received at long distances from transmitter because they are REFLECTED from the ionosphere (electrically charged layer)
  • bluetooth uses short-wave radio to send data over short distances without wire
• RADIO WAVES USES

  • MEDIUM-WAVE signals also reflect from ionosphere depending on atmospheric conditions
  • TV & FM have very short wavelengths & must be in direct sight bc signals dont travel far or bend
• MICROWAVES USES

  • satellite communication, cooking food
  • can penetrate through earths atmosphere to reach satellites
• IR USES

  • increases or monitors temperature (IR cameras)
  • transfers thermal energy
  • hotter object = more IR given out
• VISIBLE LIGHT USES

  • FIBRE OPTICS
  • best reflection in glass because they are able to refract; isnt easily absorbed as it travels along a fibre
• UV USES

  • sun tanning, energy efficient lamps (good to use for long periods)
  • radiates LEAST heat but MORE energy
• X-RAY AND GAMMA USES

  • medical imaging & treatment
  • very high in energy & can penetrate material
  • x rays can pass through flesh but not through dense materials = white stuff in x ray…
  • treat ppl w/ cancer by using high doses to kill living cells