Wave PT2

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Created by
dom

Cards (10)

  • Longditudinal waves

    • Particles move backwards and forwards.
    • The vibrations are parallel to the direction of wave travel.
    • Examples: Sound waves, ultrasound, seismic-P waves
  • Transverse wave
    • Particles move up and down.
    • The vibrations are perpendicular to the direction of wave travel.
    • Examples: Electromagnetic waves, ripples on the surface of water.
  • Electromagnetic spectrum

    • Can travel through a vacuum, red light has the lowest frequencies of visible light.
  • Polarisation

    • Light is made up of transverse waves that oscillate at different angles relative to the direction of propagation.
    • Electromagnetic waves can be polarised. A polarising filter will remove any oscillations at a 90-degree angle to the filter.
    • The waves can pass through a filter if aligned with it.
    • If the second filter is turned at 90 degrees relative to the first, it will stop light from coming through.
  • Satellite communications | High power signals over long distances
    • Frequency Band: 1 - 40 GHz (microwaves)
    • Transponders receive signals, amplify them and retransmit them as a different signal on a different frequency band.
  • Mobile phone | High power network system with a range of 7km
    • Frequency Band: 800 MHz - 2.48GHz
    • The higher the frequency, the greater the capacity, but travels less distance through the air and penetrates less well through buildings.
  • Bluetooth | Low power device with a range of 10m
    • Frequency band: 2.4 - 2.48 GHz
    • Bluetooth is used to disrupt wifi devices because both devices would be on the same channel for extended periods. Nowadays, Bluetooth uses frequency hopping (broadcasting in short bursts on different frequency channels).
    -> This reduces the amount of data lost.
  • Wi-Fi | Medium power device with a range of 10m - 100m
    • Frequency band: Between radio and microwaves
  • Infrared | Low power with a range of a few metres

    Used for remote controls and data transfers between computers and phones.
  • Wave speed = Frequency x Wavelength