Topic 4-Waves

• What do waves transfer without transferring matter?

  Energy
• How do waves behave in the sea with respect to buoys?

  Waves move, but buoys stay still
• What is the definition of wavelength?

  Distance between consecutive wave points
• What is amplitude in wave terminology?

  Distance from equilibrium to maximum displacement
• How is frequency defined?

  Number of waves passing a point per second
• What does the period of a wave refer to?

  Time taken for a whole wave to pass
• What is a wavefront?

  The plane in which the wave travels
• What is the formula for wave velocity?

  $v =$$f\lambda$
• What happens to wave velocity when frequency increases?

  Velocity increases
• What is the relationship between wavelength and velocity?

  Wavelength increases, velocity increases
• How is the period related to frequency?

  Period is inversely proportional to frequency
• How do vibrations occur in transverse waves?

  At right angles to the direction of travel
• What type of waves are longitudinal waves?

  Sound waves and seismic P waves
• What type of waves are transverse waves?

  Light and electromagnetic waves
• How do vibrations occur in longitudinal waves?

  In the same direction as travel
• What are the methods to measure sound velocity in air?

  • Noise echo method
  • Two microphones with datalogger
• How can you measure the velocity of ripples on water?

  • Use a stroboscope
  • Move a pencil at wavefront speed
• What happens to waves when they pass into a more optically dense medium?

  They bend towards the normal
• What occurs to the speed of a wave when it enters a denser medium?

  Speed decreases
• How does wavelength change when a wave enters a denser medium?

  Wavelength decreases
• What is the relationship between energy and frequency of a wave?

  Energy is directly linked to frequency
• What happens to light when it reflects off a flat surface?

  It reflects at the same angle
• How does surface smoothness affect wave reflection?

  Smoother surfaces reflect waves stronger
• What is the angle of incidence equal to?

  Angle of reflection
• What happens to light when it hits an opaque object?

  It reflects if not absorbed
• What occurs during wave transmission?

  Waves pass through a transparent material
• What happens when light frequency matches electron energy levels?

  Light is absorbed by electrons
• What happens to absorbed light energy over time?

  It is reemitted as heat
• What does it mean if a material appears green?

  Only green light is reflected
• How do different substances interact with waves?

  They may absorb, transmit, refract, or reflect
• What collects sound in the ear?

  Outer ear
• What happens to sound waves as they travel down the ear canal?

  They remain pressure air waves
• What vibrates when sound waves hit the eardrum?

  The eardrum itself
• How do the small bones in the ear respond to sound waves?

  They vibrate at the same frequency
• What do the vibrations of the bones in the ear transmit to?

  The fluid in the inner ear
• What do the small hairs in the cochlea respond to?

  Different sound frequencies
• What happens when a hair in the cochlea moves?

  It releases an electrical impulse to the brain
• How does frequency relate to the energy of a wave?

  Higher frequency means more energy
• What is the frequency range the ear can effectively hear?

  Limited frequency range
• What is ultrasound?

  Sound wave with frequency over 20,000 Hz