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• what are the 2 types of waves?

  transverse and longitudinal
• What is a transverse wave?


  waves in which the particles vibrate in an up and down motion
• What is a longitudinal wave?

  A wave in which the vibration of the medium is parallel to the direction the wave travels
• How do waves transfer energy?

  by the vibration of particles in a medium

  
  

  
  

  eg if a stone is dropped into a pond, ripples travel outwards carrying the energy. The water does not travel outward (other wise it would leave a hole in the middle)
• Explain what happens when the particles in a wave vibrates?


  the particles of a wave oscillate (vibrate) around a point.

  
  

  in doing so, they pass the energy on to the next particles, which also oscillate. and it continues
• give an example of a transverse wave

  a water wave
• give an example of a longitudinal wave

  sound wave
• how does energy move in a transverse wave

  in a transverse wave the oscillations (vibrations) are

  
• how does energy move in a longitudinal wave

  in longitudinal wave the oscillations are parallel to the direction of energy transfer

  
• what are the 4 properties of waves

  frequency (the number of waves passing through a point per second)

  
  

  amplitude ( the maximum displacement that any particle achieves from its undisturbed position - in metres)

  
  

  wavelength (distance from one point of wave to the equivalent point on the next wave = in metres)

  
  

  period (time it takes for one complete oscillation in seconds)

  
• in water waves, what is amplitude

  wave height
• in water waves, what is a period

  the time it takes for one complete wave to pass a fixed point
• what is the equation for wave period

  wave period = 1

  --------------------

  frequency

  
  

  or T = 1

  ----------

  f

  
  

  T (period) is measured in seconds (s)

  
  

  f = frequency is measured in hertz (Hz)
• What is wave speed?

  The speed at which energy is being transferred or the speed at which the wave is moving at
• what is the equation for wave speed

  wave speed = frequency x wavelength

  v = f x λ

  
  

  wave speed (v) is measured in metres per second (m/s)

  frequency (f) is measured in hertz (Hz)

  wavelength (λ) is measured in metres (m)
• REQUIRED PRACTICAL

  
  

  identify the suitability of apparatus to measure the frequency, wavelength and speed of waves in a ripple tank


  test time it takes one wave to travel the length of the tank.

  use this to calculate wave speed using

  speed = distance / time

  
  

  to find the frequency, count the number of waves passing a fixed point in a second

  
  

  estimate the wavelength by using a ruler to measure the peak to peak distance as the waves travel

  
  

  use a stroboscope to make the same measurements and compare the results

  
  

  VARIABLES:

  
  

  water depth - must be kept constant or it will affect the speed and wavelength

  
  

  using a stroboscope can significantly increase accuracy of measurements. by projecting the shadow of the waves onto a screen below the stroboscope, flash speed can be adjusted to make waves seem stationary. this makes wavelength measurements more accurate

  
  

  for high frequencies difficult to count you can use the wave speed measurement v = f x λ
• risk of using stroboscope


  it can affect people with photo sensitive epilepsy
• why can using a stroboscope make wave measurements more accurate

  using a stroboscope can significantly increase accuracy of measurements. by projecting the shadow of the waves onto a screen below the stroboscope, flash speed can be adjusted to make waves seem stationary. this makes wavelength measurements more accurate
• in what direction are the oscillations in a transverse wave?

  A transverse wave is a moving wave that consists of oscillations occurringperpendicular (or right angled) to the direction of energy transfer.
• Work out the period of a wave with a frequency of 20Hz


  Answer: Time period is the reciprocal of frequency. Hence, T=1/f = 1/(20 Hz) =0.05 secs.
• What are electromagnetic waves?

  Transverse waves that transfer energy from the source of the waves to an absorber.
• What speed do electromagnetic waves travel at?

  speed of light
• What is refraction?


  the bending of waves due to a change in speed
• what does the direction of refraction depend on?

  the angle at which the wave hits the boundary

  
  

  the materials involved
• what happens when light travels from a material with a low refractive index to one with a higher refractive index?

  the light bends towards the normal
• what happens when light travels from a material with a high refractive index to one with a lower refractive index?

  light bends away from the normal
• Give the order of waves in the Electromagnetic Spectrum?


  In order from highest to lowest energy, the sections of the EM spectrum are named:gamma raysX-raysultraviolet radiationvisible lightinfrared radiationand radio waves.

  Microwaves (like the ones used in microwave ovens) are a subsection of the radio wave segment of the EM spectrum.

  
• What is a ray diagram?

  a diagram that traces the path that light takes in order for a person to view a point on the image of an object
• what happens when waves reach a boundary between one medium (material) and another

  they can be refracted
• how do you construct a ray diagram

  rays must be drawn with a ruler

  
  

  each straight section of a ray should have a single arrow drawn on it to indicate the direction of movement

  
  

  where the ray meets the boundary, the 'normal' should be drawn at right angles to the boundary

  
  

  all relevant angles should be labelled

  
• When are ray diagrams used?

  whenever a diagram is needed to represent how light moves from one place to another (eg reflection)
• list the types of wave in the electromagnetic spectrum in order from long to short wave length

  radio wavesmicrowavesinfraredvisible lightultravioletx-raysgamma rays.See an expert-written answer!We have an expert-written solution to this problem!
• on a ray diagram what is the 'normal'?

  A line drawn at right angles to the surface at the point of origin
• a light wave travels from one medium to another. as it crosses the boundary, it changes direction.

  what is the name given to this effect?

  refractionSee an expert-written answer!We have an expert-written solution to this problem!
• describe the difference between transverse and longitudinal waves

  longitudinal waves oscillations (vibrations) are parallel to the direction of energy transfer (eg sound waves)

  
  

  transverse waves oscillations are perpendicular (right angles) to the direction of energy transfer (eg water waves)
• describe evidence that waves transfer energy not matter

  For example,if a ball is placed on the surface of a pond when ripples move across it, the ball will move up and down but not outwards with the w
• describe waves in terms of amplitude, wavelength, frequency and period


  amplitude - maximum displacement of the wave from its undisturbed position in metres

  
  

  wavelength - the distance from one point of a wave to the equivalent point on the next wave in metres

  
  

  frequency - the number of waves passing a fixed point per second measured in hertz (Hz)

  
  

  period - the time taken of one complete oscillation in metres
• explain how speed, frequency and wavelength are linked

  wave speed = frequency x wavelength
• what are radio waves?

  radio waves are low energy waves , not harmful , ideal for radio transmission

  ( TV, radio, bluetooth)
• what are microwaves?


  microwaves travel in straight lines through the atmosphere.

  it makes them idea for transmitting signals to satellites in orbit and back down to receivers

  (eg satellite communication, cooking food)