WAVES

• what is a transverse waves


  ocallisions are perpendicular to the direction of the energy transfer
• example of a transverse wave


  ripples and waves on water
• what is a longitudinal wave


  the ocallisions are parallel to the direction of energy transfer
• example of longitudinal waves


  sound waves
• define amplitude 


  the amplitude of a wave is the maximum displacement of a point on the wave from its undisturbed position
• define wavelength


  the distance between the same point on two adjacent waves
• define frequency


  number of waves passing a point each second
• frequency = 1/period
• formula for wave speed


  = frequency x wavelength in m
• what can happen when waves arrive at a boundary between two different materials


  absorbed, reflected or transmitted
• angle of i


  = angle of r
• what is an electromagnetic wave


  transverse waves that transfer energy from a source to an absorber
• the spectrum goes from


  lowest energy

  lowest frequency

  highest/longest wavelength

  to

  highest energy

  highest frequency

  lowest/shortest wave length
• what angle do electromagnetic waves oscillate at


  90
• what are radio waves made from


  oscillating charges
• uses of radio waves


  communications
• radio waves transmit


  radio signals and terrestrial tv signals
• why are radio waves used


  they can travel long distance before being absorbed by buildings and trees
• how can you produce radio waves

  using an ac in a circuit the object in which charges oscillate o create the radio waves is called a transmitter. when transmitted radio waves reach a reciever , the radio waves are absorbed
• uses of microwaves


  communication and microwaves and satellites
• uses of radio waves


  communications,

  long waves radio wavelengths can also diffract around hills, and bend around the curved surface of the earth

  short wave radio signals can be received at long distances from the transmitter
• uses of microwaves with satellites


  the signal form a transmitter is transmitted into space, where its picked by the satellite receiver, the satellite transmits the signal back to earth in a different direction. where its received on a satellite dish on ground
• how to microwaves work is MICROWAVES


  the microwaves are absorbed by water molecules in food

  absorbed and transfer the energy to the water molecules causing the water to heat up the water molecules then transfer this to the rest by heating,,, heating up your food
• what is inferred radiation


  its given out by all objects and the hotter the object the more IR radiation it gives out
• uses of infrared radiation


  infrared cameras can be used to detect radiation and monitor temperature

  the camera detects the IR and turns it into an electrical signal

  hotter=brighter

  redder=more inferred
• how do electric heaters work


  contain a long piece of wire that heats up- this wire then emits lots of infrared radiation. the emitted IR radiation is absorbed by the objects in the room.

  energy is transferred by the ir waves to the thermal energy stores- causing temp to inrease
• uses of ultraviolet waves


  gives you a suntan

  fluorescent light generate UV radiation which is absorbed and re emitted as visible light by a layer of compound called phosphor on the inside of the bulb

  sun tan

  uv lamps
• uses of x rays and gamma rays


  radiographers in hospitals take x-rays photographs

  pass through flash but no so easily through denser materials like bones or metals

  gamma rays kill cancer cells
• difference between x rays and gamma rays


  x rays are produced when electrons or other particles moving at high speed are stopped

  gamma rays are realised when an unstable nuclei releases energy

  gamma rays are shorter than x-rays and penetrate more
• describe sound waves


  sound waves can travel through solids causing vibrations in the solid
• how do sound waves work in the human ear


  the human ear detects sound

  sound waves enter the ear canal and cause the cardiac to vibrate

  these small bones transmit these vibrations to the cochlea this produces electrical signals which pass through the auditory nerve to the brain
• properties of sound waves if high freq


  they are high pitched
• properties of sound waves if low freq


  sounds waves are Low pitched
• if they have a high or low amplitude


  high=high volume

  low=low volume
• whats the range of normal human hearing?


  20hz-20khz
• ultrasound waves


  have a frequency higher than the upper limit for humans
• how Are ultrasound waves reflected


  partially reflected when meet a boundary between two different media

  time taken for the reflections to reach a detector can be used to determine how far away such a boundary is
• uses of ultrasound


  cleaning jewellery

  medical

  breaking kidney stones
• echo sounding is


  high frequency waves that are used to detect objects in deep water and measure water depth
• what are seismic waves produced by


  earthquakes