Waves-physics

• Examples of transverse waves

  • Electromagnetic waves
  • Seismic s-waves
• A transverse wave is a wave for which the oscillations are perpendicular to the direction of energy transfer
• A longitudinal wave is a wave for which the oscillations are parallel to the direction of energy transfer
• Two types of waves are Transverse and Longitudinal
• Examples of longitudinal waves

  • Sound waves
  • Seismic p-waves
• Parts of a longitudinal wave

  • Compressions
  • Rarefactions
• Frequency of a wave


  The number of complete wavelengths that pass a point in a given time
• Wavelength


  The distance from a point on a wave to the same position on the adjacent wave. Most commonly peak to peak or trough to trough
• Wave's amplitude

  The maximum displacement of a point on a wave from its undisturbed position
• Frequency of 200Hz means 200 waves pass a given point each second
• Point on a wave to the same position on the adjacent wave
• Frequency of a wave

  • The number of waves that pass a given point each second
• Wave speed is the speed at which the wave moves or at which energy is transferred through a medium
• Equation used to calculate wave speed: Wave Speed = Frequency x Wavelength. Units: Speed (m/s), Frequency (Hz), Wavelength (m)
• Word used to describe when a wave bounces off a surface is Reflection
• Wave transfers energy
• How sound waves travel through a solid: The particles in the solid vibrate and transfer kinetic energy through the material
• Frequency range of human hearing is 20 Hz - 20kHz
• Ultrasound waves have a frequency higher than the upper limit of human hearing (20kHz)
• Seismic waves are produced by earthquakes and produce both P-waves and S-waves
• Difference between P-waves and S-waves: P-waves travel through both solids and liquids, while S-waves only travel through solids (not liquids)
• Technique used to detect objects in deep water and measure water depth is echo sounding. High frequency sound waves are emitted, reflected, and detected. The time difference between emission and detection, alongside wave speed, is used to calculate distances
• Electromagnetic waves all travel at the same speed in a vacuum and in air
• Order the types of electromagnetic radiation from lowest to highest frequency

  1. Radio waves

  2. Microwaves

  3. Infrared

  4. Visible Light

  5. Ultraviolet

  6. X-rays

  7. Gamma Rays
• When radio waves are absorbed, they can induce oscillations in a circuit with the same frequency as the waves themselves
• Property causing refraction in different mediums

  • Velocity
  • Wave speed is slower in denser materials, causing refraction
• Direction of waves when entering a denser medium

  • They bend towards the normal
  • The angle of refraction is less than the angle of incidence
• Radio waves can be produced by oscillations in an electrical circuit
• Electromagnetic waves form a continuous spectrum
• Gamma rays originate from changes in the nuclei of atoms
• Ultraviolet waves can cause the skin to age prematurely and increase the risk of developing skin cancer
• Oscillations in a circuit have the same frequency as the waves themselves
• 1. rays and Gamma rays, being ionising radiation, can cause mutations in genes and lead to an increased risk of developing various cancers
• A convex lens forms an image by refracting parallel rays of light and bringing them together at a point known as the principal focus
• Practical uses for radio waves

  • Television transmission
  • Radio transmission
• Practical uses for infrared radiation


  • Electrical heaters
  • Cooking food
  • Infrared cameras
• Practical uses for microwave radiation

  • Satellite communications
  • Cooking food
• The focal length of a lens is the distance from the lens to the principal focus
• Refraction is the wave phenomenon used by lenses to form an image
• Concave lenses can only produce virtual images