physics semester 2

• what is a wave?

  A disturbance or oscillation that travels through space and time, carrying energy without transporting matter.
• what is a longitudinal wave?


  A wave in which the particles of the medium oscillate parallel to the direction of wave propagation. The compressions and rarefactions in the medium correspond to the wave's crests and troughs. An example of a longitudinal wave is a sound wave in air.
• what is a transverse wave?


  A wave in which the particles of the medium oscillate perpendicular to the direction of wave propagation. The crests and troughs of the wave correspond to the maximum and minimum displacements of the particles. An example of a transverse wave is a wave on a string or electromagnetic waves such as light.
• properties of a wave

  frequency - number of waves produced each second

  wavelength - refers to the distance between two adjacent waves (directly next to each other)

  amplitude - The amplitude of a transverse wave is the maximum distance that each particle extends past its resting position. amplitude of a longitudinal wave is the distance between two adjacent compressions or rarefactions

  period (T) - the time for a particle to make one full cycle of the wave
• what is the wave equation?

  speed/velocity (v)\, wavelength (Λ) and frequency (f)

  v=fΛ
• what does the law of reflection state?

  no matter which direction light hits a smooth surface from, the light reflects back off at an equal angle. angle of incidence = angle of reflection
• what is the incident ray?

  Incoming
• what is the reflected ray?

  Reflection
• what is the normal?


  an imaginary line drawn perpendicular to the surface the light strikes
• what is refraction?

  Refraction is the 'bending' of light as it travels through different substances of different densities on an angle
• when travelling from low to high density, which direction does the light move from the normal

  toward
• when travelling from high to low density, which direction does the light move from the normal

  away
• depending on the density of a medium, what speed will light travel through it?

  the denser the medium, the slower the light will travel
• how does light speed up?

  when a medium is less dense there is less disruption, and more dense is more disruption. this is due to the particles of the medium being closer (dense) and farther apart (sparse)
• what is refraction?

  refraction is light waves changing speed when they pass between two substances of different densities, which causes the light waves to change direction.
• what colour has the highest frequency

  violet (think of a rainbow, red, orange, yellow, green, blue, indigo, violet)
• how can someone determine the frequency of water rippling

  1. count the number of ripples
  2. measure the time
  3. calculate the frequency (f=number of ripple/time taken(s))
• alpha rays

  • also known as helium
  • +2 charge
  • 4 atomic mass units
  • low penetration power
  • high hazard risk
  • can be dangerous in ingested or inhaled
• beta rays

  • -1 charge
  • has barely any mass
  • moderate penetration power
  • moderate hazard risk
  • can be dangerous if not shielded from properly
• gamma rays

  • have no mass and no charge
  • high penetration level
  • low hazard risk
  • less likely to be dangerous to humans
• order of EM spectrum highest to lowest

  gamma, x-ray, uv, visible light, infrared, microwave, radio
• waves are oscillations that transfer energy through space without moving matter
• the electromagnetic spectrum is made up of waves that have different wavelengths and frequencies.
• longitudinal waves have peaks and troughs parallel to direction of travel
• transverse waves have peaks and troughs perpendicular to direction of travel