Waves

• What are the two types of waves?

  Transverse and longitudinal.
• What is transverse wave?

  A wave for which the oscillations are perpendicular to the direction of energy transfer.

  
• What is longitudinal wave?

  A wave for which the oscillations are parallel to the direction of energy transfer

  
• Two examples of transverse waves

  Electromagnetic waves and seismic s-waves
• Two examples of longitudinal waves

  Sound waves and seismic p-waves
• What are the two parts of longitudinal waves called?

  Compression and refraction
• What is waves amplitude?

  The maximum displacement of a point on a wave
• What is a wavelength?

  The distance distance from one entire oscillation

  Most commonly peak to peak or trough to trough

  
• What is frequency of a wave?

  Number of waves that pass a given point each second
• What is the unit for frequency?

  Hertz, Hz
• what is meant by a frequency of 200Hz?

  200 waves pass a given point each second
• What is wave speed?

  The speed at which a wave travels through a medium(density).
• What does a wave transfer?

  Energy
• Stage equation to calculate wave speed

  Wave speed= frequency x wavelengths

  Speed(m/s), frequency (Hz), wavelength (m)
• What word is used to describe when a wave bounces off a surface?

  Reflection
• How do sound waves travel through a solid?

  Particles in solid vibrate and transfer kinetic energy through the material
• What is the frequency of human hearing?

  20 Hz - 20kHz

  (1kHz = 1000 Hz)
• What are ultrasound waves?

  Waves which have a frequency higher than the upper limit of human hearing
• Give an example use for ultrasound waves?

  Medical or industrial imaging
• What type of spectrum do electromagnetic waves form?

  A continuous spectrum
• order the types of EM radiation form lowest to highest frequency

  radio waves

  micro waves

  infra red

  visible lights

  ultra violet

  x-rays

  gamma rays
• How does the speed of EM radiation differ in a vacuum and in air?

  EM waves all travel at the same speed in a vauum and in air
• What property of waves in different mediums causes refraction?

  velocity

  Wave speed is slower in denser materials causing refraction
• In which direction (relative to the normal ) do waves refract when entering a denser medium?

  • They bend towards the normal
  • The angle of refraction is less that the angle of incidence

  
• Rules for ray diagrams

  Angle of incidence = angle of reflection
• What is specular reflection?

  Reflection of light off a smooth surface, when boundary is smooth the normals are in same direction so light reflected in same directions.

  Creates a clear image
• What is diffuse/ scattered reflection?

  When the boundary is bumpy , normals will all be at at different angles so light reflected in different angles

  Normally can’t see ourselves
• What happens to speed of wave travelling in a high density?

  Slower speed
• What are electromagnetic waves made up of?

  Oscillating electric and magnetic fields
• What are electromagnetic (EM) waves used for?

  Various applications, especially entertainment
• How do radio waves transfer energy?

  To car radios and TVs
• What are EM waves made of?

  Oscillating electric and magnetic fields
• What produces alternating currents (ac)?

  Oscillating charges
• What happens when charges oscillate?

  They produce electromagnetic waves
• What is the relationship between wave frequency and alternating current frequency?

  They are equal
• How can you produce radio waves?

  Using an alternating current in a circuit
• What is the role of a transmitter?

  To create radio waves
• What happens to radio waves when they reach a receiver?

  They are absorbed
• What occurs when radio waves are absorbed by a receiver?

  Electrons in the material oscillate
• What does the energy from absorbed radio waves do?

  It causes electrons to oscillate