P12 Waves Properties

• What do mechanical waves require to travel through?

  A substance (a medium)
• Name an example of a mechanical wave.

  Sound waves
• How do particles behave when waves travel through a substance?

  They oscillate and pass energy to neighbors
• What do waves transfer from one place to another?

  Energy
• What are the two types of waves mentioned?

  Transverse and longitudinal
• What happens when a light object is dropped into still water?

  It produces ripples that spread out
• How do sound waves travel when you speak?

  They travel through the air without moving it
• In a transverse wave, how are the oscillations oriented?

  Perpendicular to the direction of energy transfer
• What is an example of a transverse wave?

  Ripples on the surface of water
• How do oscillations in a longitudinal wave behave?

  They are parallel to the direction of energy transfer
• What do longitudinal waves produce in a substance?

  Areas of compression and rarefaction
• What is an example of a longitudinal wave?

  Sound waves
• What is amplitude in wave properties?

  Maximum displacement from undisturbed position
• What unit is amplitude measured in?

  Metre (m)
• What does frequency measure in wave properties?

  Number of waves passing a fixed point per second
• What unit is frequency measured in?

  Hertz (Hz)
• What is the period of a wave?

  Time taken for one complete wave to pass
• What unit is period measured in?

  Second (s)
• What is wavelength in wave properties?

  Distance from one point on a wave to the next
• What unit is wavelength measured in?

  Metre (m)
• What does wave speed measure?

  Distance travelled by each wave per second
• What unit is wave speed measured in?

  Metres per second (m/s)
• What is the relationship between frequency and period?

  Period = 1 / frequency
• What is the wave equation?

  Wave speed = frequency × wavelength
• What is the frequency range of ultrasound?

  Greater than 20,000 Hz
• What happens to speed and wavelength when waves travel from one medium to another?

  Speed and wavelength may change, frequency stays the same
• How can the speed of ripples on water be measured?

  Using a stopwatch and ruler
• Why can't humans hear ultrasound?

  It has frequencies too high for humans
• What happens when waves arrive at the boundary between two substances?

  They can be absorbed, reflected, refracted, or transmitted
• Which animals can hear ultrasound?

  Dogs, cats, and bats
• What is absorption in wave behavior?

  Energy is transferred to the energy stores of the substance
• What is reflection in wave behavior?

  Waves bounce back
• What are the properties of ultrasound compared to sound?

  • Frequencies greater than 20,000 Hz
  • Similar properties to sound
• What is refraction in wave behavior?

  Waves change speed and direction
• What is transmission in wave behavior?

  Waves carry on moving at a different speed
• What two factors are needed to calculate the distance to the sea bed?

  Time taken and speed of sound in water
• What is the formula to calculate the depth of water?

  Depth = ½ t x v
• What are the steps to draw a ray diagram for reflection?

  1. Use a ruler for rays
  2. Draw an arrow for wave direction
  3. Draw a normal line at incidence point
  4. Label normal, angle of incidence (i), and angle of reflection (r)
• What is the relationship between the angle of incidence and angle of reflection?

  They are always equal (i = r)
• What is the speed of sound in water?

  1500 m/s