Waves

• Define frequency

  The number of complete waves passing a point per second
• What is frequency measured in?

  Hertz
• What is the top of a wave called?

  Peak
• What is the bottom of a wave called?

  Trough
• What is the distance from the centre line to the peak of a wave called?

  Amplitude
• In which wave are the direction of oscillations perpendicular to the direction of energy tranfer - transverse or longitudinal?

  Transverse
• Which direction are the oscillations in a transverse wave?

  Up and down
• In which type of wave is the direction of oscillation parallel to the direction of energy transfer - transverse or longitudinal?

  Longitudinal
• How can you remember which wave has perpendicular oscillations and energy transfer and which has parallel?

  The T in transverse is like a right angle and the Ls in longitudinal are parallel to eachother
• What is the equation for a period?

  T= 1/f
• What is the symbol for period?

  T
• What is period measured in?

  Seconds
• What is the equation for wave speed?

  Wave speed = frequency x wavelength
• Describe how to use a ripple tank to find wave speed

  Adjust the wooden bar and turn on the motor so it vibrates on the surface of the water creating waves. Measure the length of 10 wave lengths by placing a ruler on the card beneath the tank and taking a photo of it. Use the photo to measure 10 wavelengths and divide by 10. For frequency, mark a point on the card and take a slow motion video with a 10 second timer in it to count the number of waves passing the point in 10 seconds then divide by 10. Do frequency x wavelength to calculate the wave speed.
• Are electromagnetic waves transverse or longitudinal?

  Transverse
• When are electromagnetic waves all the same speed?

  In a vacuum
• How many electromagnetic waves are there?

  7
• How can you remeber the order of electromagnetic waves (long wavelength to short)?

  Ronald Macdonald Is Very Ungry Xtra Gerkins
• Which wave has the longest wavelength?

  Radio
• Which wave has the highest frequency?

  Gamma
• Which wave has the shortest wavelength?

  Gamma
• Which wave has the lowest frequency?

  Radio
• What can microwaves be used for?

  Satellite communications, microwave oven
• What can infrared waves be used for?

  Thermal cameras, electric heaters
• What can visible light waves be used for?

  Fibre optic cables
• What can ultraviolet waves be used for?

  Invisible ink, tanning salons, UV light
• What can gamma waves be used for?

  Radiotherapy for cancer, medical tracer, sterilise hospital equipment
• Do radio waves have a high or low frequency?

  Low
• Do gamma waves have a high or low frequency?

  High
• What is the acronym to remember wave order?

  Ronald Mcdonald Is Very Ungry Xtra Gherkins
• What is the suffix for nanometres?

  × 10 ^ -9
• Why do waves refract when passing from air into a liquid?

  • The wave slows down as it passes from air into liquid
  • One edge of the wavefront enters liquid before the other
  • One edge slows down before the other so the wave changes direction
• What type of wave are sound waves?

  Longitudinal
• Which is faster - transverse or longitudinal?


  Transverse
• Which needs a medium to travek through - transverse or longitudinal?

  Longitudinal
• Describe how radio waves reaching the (car aerial) produces signals in the electrical circuit of the (car radio):

  • Car aerial absorbs the radio waves
  • Electrons in the aerial wire are made to vibrate/oscillate
  • This creates an alternating current
  • The signal frequency is the same as the radio wave
• What can radio waves create when absorbed?

  Alternating current with the same frequency as the radio wave itself
• What can radio waves do?

  Induce oscillations in an electrical current
• Which colour of visible light has the longest wavelength?

  Red
• Which colour of visible light has the highest frequency?

  Violet