Waves

• The period of a wave is how long one full cycle of the wave takes.
• The frequency of a wave is how many cycles occur in one second.
• Shock waves in the Earth are called seismic waves.
• All sound waves are longitudinal.
• Areas of rarefaction are areas where the particles are far apart.

  Number 1
• The frequency of an ultrasound wave is the number of waves that pass a particular point in one second
• In transverse waves the vibrations are perpendicular to the direction of energy transfer.
• Wavelength is the distance between any point on one wave and the equivalent point on the next wave.
• The wavelength of an ultrasound wave is the distance between one region of compression or rarefaction and the next.
• Water is a transverse wave, so the vibrations are perpendicular to the direction of the wave motion. The wave spreads out along the surface of the water, so the water particles move up and down.
• Seismic waves are produced by earthquakes, and travel through the Earth, giving us information about the Earth's structure.
• The more energy a sound wave carries, the louder the sound and the bigger its amplitude
• In transverse waves the vibrations are perpendicular to the direction of energy transfer.
• Amplitude is the maximum a point moves from it's rest position when a waves passes.
• Frequency is the number of waves passing a point in one second.
• Sound is a longitudinal wave.
• When water ripples the water particles are moving up and down.
• Pitch is dependent on the frequency of the wave, and notes 1 and 2 have the same frequency.
• Notes 1 and 2 have the same frequency so will have the same pitch, but note 2 has a smaller amplitude than note 1 so will be quieter.
• The volume of a sound depends on the amplitude, and notes 1 and 3 have the same amplitude.
• Amplitude is the maximum displacement of a wave measured from the midpoint, which is bigger on sound 2 than sound 4.

  
• Pitch is dependent on the frequency of the wave, and note 4 has the highest frequency.

  
• The more energy a sound wave carries, the louder the sound and the bigger its amplitude.
• Light bends towards the normal when it slows down.

  You can use the remember this as FAST: Faster Away, Slower Towards.

  
• Glass is a more dense material than air, so light will travel more slowly in glass than air.
• An electromagnetic wave with a wavelength of 100m must be a radio wave
• An electromagnetic wave with a wavelength of 0.1mm must be an infrared wave
• gamma

  x-rays

  UV

  visible light

  infrared

  microwaves

  radio waves.
• gamma

  x-rays

  UV

  visible light

  infrared

  microwaves

  radio waves.
• gamma

  x-rays

  UV

  visible light

  infrared

  microwaves

  radio waves.
• All electromagnetic waves are transverse waves.
• X-rays have the second shortest wavelength, so gamma rays must have the shortest wavelength
• Human eyes can only see the visible light portion of the electromagnetic spectrum
• Light that reaches a glass-air boundary at an angle smaller than the critical angle will be refracted
• The critical angle is the largest incident angle that results in a refracted beam, so refraction occurs for any incident angle smaller than the critical angle.
• X-rays can be transmitted by less dense materials but are absorbed by more dense materials, making them very useful for detecting metal objects inside bags.
• Mobile phones transmit to cell masts using radio waves. The calls are transmitted from one cell tower to another via microwaves.
• Infrared radiation can be used for short distance data links for computers or mobile phones.
• Microwave ovens use microwave radiation to heat food - the microwave radiation is absorbed by water and fat molecules in the food.
• Metals are dense so can absorb X-rays.