PHYSCI 12

• Waves


  A travelling disturbance that carries energy with it
• Waves


  • Vibration causes wave motion
  • Waves travel through a medium

  
• Characteristics of Waves


  • Crests
  • Trough
  • Amplitude
  • Wavelength
  • Frequency
  • Period
  • Speed

  
• Crests


  The highest point of waves
• Trough


  Lowest point of waves
• Amplitude


  The maximum displacement from the rest position
• Wavelength


  The distance between two successive crests or two successive troughs
• Frequency


  The number of crests or troughs that pass a point per second
• Period


  The time taken to generate one complete wave
• Speed


  The distance moved by the wave in one second
• Categories of Waves


  • Mechanical Waves
  • Electromagnetic Waves
  • Matter Waves
• Mechanical Waves


  • Require a medium to travel
  • Molecules in the medium collide and exchange energy
• Transverse Waves


  • Disturbance moves perpendicular to the wave's direction

  
• Transverse Waves


  • Water waves
  • Light

  
• Longitudinal Waves


  • Disturbance moves in the same direction as the wave

  
• Longitudinal Waves


  • Sound waves
• Electromagnetic Waves


  • Can flow through a vacuum
  • Have a magnetic and electric field that are orthogonal to each other and to the wave's propagation
• Radio Waves


  Used in radio communication, television, two-way radios, cell phones, communication satellites, wireless networking, navigation, industrial heating, and remote control
• Microwaves


  Short wavelength radio waves used in microwave ovens, industrial heating, medical diathermy, radar, satellite communication, and wireless networking
• Infrared


  Radiation emitted by hot objects, absorbed by molecular vibrations, divided into near-infrared, mid-infrared, and far-infrared
• Visible Light


  The region of the electromagnetic spectrum to which the human eye is sensitive
• Ultraviolet Rays


  Shorter wavelength than visible light, powerful enough to ionize atoms and generate chemical reactions, can harm living tissue
• 1. rays


  Divided into hard and soft, can penetrate various materials, used in diagnostic imaging and high-energy physics
• Gamma Rays


  The most energetic photons, used in astronomy, physics experiments, food/seed sterilization, and cancer therapy
• Classification of Waves


  • Based on the Medium of Wave
  • Based on the Energy Transfer
  • Based on the Dimension of Propagation

  
• Mechanical Waves


  Require a medium to propagate, molecules in the medium collide and exchange energy
• Non-Mechanical Waves


  Do not require a medium to propagate, can travel through a vacuum, have a transverse nature
• Matter Waves


  Concept introduced by Louis de Broglie, also referred to as de Broglie waves

  
• Waves


  y can be sound waves, radio waves, water waves, sine waves, cosine waves, string waves, slinky waves, and so on

  
• Waves


  • Classified into several types based on their features

  
• Classification of waves based on medium

  • Mechanical waves
  • Non-mechanical waves

  
• Mechanical waves


  Require a medium to propagate, travel through some form of material, molecules in the medium collide and exchange energy
• Non-mechanical waves


  Do not require a medium to propagate, can travel through a vacuum, possess a transverse nature
• Non-mechanical waves


  • Electromagnetic waves
  • Matter waves
• Matter waves


  Concept introduced by Louis de Broglie, all matter behaves in a wave-like manner, de Broglie equation connects wavelength and momentum

  
• Classification of waves based on energy transfer

  • Standing waves
  • Progressive waves

  
• Standing waves


  Stationary, no transfer of energy and momentum, created by superposition of two harmonic waves of equal amplitude and frequency travelling in opposite directions

  
• Progressive waves


  Transfer energy and momentum through wave motion, can travel indefinitely without stopping or changing in amplitude or direction
• Classification of waves based on dimension of propagation

  • 1D waves
  • 2D waves
  • 3D waves

  
• 1D waves


  Waves produced in a single direction, example: spring waves