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Physics Unit 4- waves

Adeline Göttle Alemán 59 fichas

Physics Unit 4- waves

Fichas del conjunto (59)

  1. 1Oscillations definitionOscillations are periodic motions which center around an equilibrium position.
  2. 2SHM examples [3]1. The simple pendulum
    2. The vibration of strings in a violin
    3. The spring-mass system, where the mass is initially displaced to produce a periodic motion around the equilibrium position
  3. 3When does an object undergo simple harmonic motion?An object undergoes SHM if it experiences a force which is proportional and opposite of the displacement from its equilibrium position
  4. 4SHM pendulum equationSHM pendulum equation
  5. 5SHM spring-mass system equationSHM spring-mass system equation
  6. 6Displacement (x) definitionDisplacement of the oscillating object at a specific time from its equilibrium position
  7. 7Amplitude definitionMaximum displacement of the oscillating object
  8. 8Period (T) definitionTime taken for one complete oscillation (in seconds)
  9. 9Frequency (f) definitionNumber of times the object oscillates per unit time (usually one second)
    f=1/T
  10. 10Phase difference definitionThe difference between two SHMs with the same frequency in terms of their relative position in a cycle measured in radian
  11. 11Conditions for SHM1. When the body is displaced from equilibrium, there must exist a restoring force (a force that wants to pull the body back to equilibrium).
    2. The magnitude of the restoring force must be proportional to the displacement of the body and acts towards the equilibrium.
  12. 12Travelling wave definitionA travelling wave is a continuous disturbance in a medium characterized by repeating oscillations. (e.g. a rope that is flicked up and down continuously)
  13. 13Travelling waves characteristics [3]Energy is transferred by waves.
    Matter is not transferred by waves.
    The direction of a wave is defined by the direction of the energy transfer.
  14. 14Transverse wavesThe direction of oscillation is perpendicular to the direction of the wave (e.g. water wave & light)
  15. 15Longitudinal wavesThe direction of oscillation is parallel to the direction of the wave (e.g. Wave produced by springs & sound)
  16. 16crestA point with maximum positive displacement
  17. 17troughA point with minimum displacement
  18. 18compressionA region where particles are closed to each other
  19. 19rarefactionA region where particles are furthest apart from each other
  20. 20EM waves characteristics- All EM waves travel in vacuum at the same speed of 3*10^8m/s
    - EM waves are transverse waves
  21. 21EM wave ranked by wavelength (small to big) (--> frequency is the opposite way around)Gamma (10^-12), X-Ray, Ultraviolet, Visible, Infrared, Microwave, Radio (10^3)
  22. 22EM wave frequency, temperature and colourEM wave frequency, temperature and colour
  23. 23Speed of sound estimationThe speed of sound in 20 degrees Celsius dry air is approximately 343.2m/s.
  24. 24Wavefronts- Lines joining points which vibrate in phase.
    - Can be straight lines or curves.
    - The distance between successive wavefronts is the wavelength of the wave.
  25. 25Rays- Lines which indicate the direction of wave propagation.
    - Rays are perpendicular to wavefronts.
  26. 26What do amplitude and intensity of a wave depend on?Its energy
  27. 27Principle of superpositionThe principle of superposition states that the net displacement of the underlying medium for a wave is equal to the sum of the individual wave displacements.
  28. 28Polarisation- Polarisation can only occur to transverse waves
    - polarisation of light refers to the orientation of the oscillation in the underlying electric field
    - Light is plane polarised if the electric field oscillates in one plane
  29. 29"Partially polarised" meaningThe light is a mixture of polarised light and unpolarised light
  30. 30What does the extent of reflected polarised light depend on?The extent to which the reflected light is polarised depends on the angle of incidence and the refractive index of the two mediums.
  31. 31Polariser- a sheet of material which polarises light.
    - When unpolarised light passes through a polariser, its intensity is reduced by 50%.
  32. 32Analyser- When polarised light passes through a polariser, its intensity will be reduced by a factor dependent on the orientation of the polariser. This property allows us to deduce the polarisation of light by using a polariser.
    A polariser used for this purpose is called an analyser.
  33. 33Reflectionangle of incidence = angle of reflection
  34. 34Reflection of waves from fixed and free ends.Reflection of waves from a fixed end is inverted.
    Reflection of waves from a free end is not inverted.
  35. 35Refractionthe change in direction of a wave when it transmits from one medium to another.
  36. 36Snell's lawn1/n2= sin2/sin1
  37. 37In Snell's law, what is n?Refractive index
  38. 38Fast to slaw refractive index vs slow to fast refractive index wave behaviourFast-to-slow: towards normal
    slow-to-fast: away from normal
  39. 39If angle of incidence is less than critical angle...most of the light passes through
  40. 40If angle of incidence is equal to critical angle...most of the light travels along the surface and quite a lot is reflected back
  41. 41If angle of incidence is greater than the critical angle..all the light is reflected back
  42. 42Equation relating critical angle and refractive indexEquation relating critical angle and refractive index
  43. 43When does total internal reflection take place?only when the light ray propagates from a optically denser medium to an optically less dense medium
  44. 44Interference patternsMaximums form at constructive interference and minimums form at destructive interference
  45. 45Constructive/Destructive interference conditionsConstructive/Destructive interference conditions
  46. 46Conditions necessary for interference of lightBOTH WAVES:
    - same frequency
    - travelling in same directions
    - amplitude same or similar
    - sources (slits) thin
  47. 47Standing wavesStanding waves (stationary) waves result from the superposition of two opposite waves which are otherwise identical.
  48. 48Standing waves characteristics- No energy transfer
    -A wave hits a wall and is reflected identically opposite.
  49. 49Open-closed standing wave equationOpen-closed standing wave equation
  50. 50Open-open or closed-closed standing wave equationOpen-open or closed-closed standing wave equation
  51. 51NodesPositions along the wave which are fixed are called nodes
  52. 52AntinodesPositions along the wave with the largest displacement are called antinodes
  53. 53Differences between traveling and standing waves [4]Differences between traveling and standing waves [4]
  54. 54Pipe closed at 1 end (L=..)L=(2n+1)* Lambda/4
  55. 55Pipe open & closed at both ends (L=...)L=n' * Lambda/2
  56. 56Out of phase (how much phase difference)180 degrees, pi radians or lambda/2 phase difference
  57. 57In phase (how much phase difference)O degree phase difference or Lambda out of phase
  58. 58Critical angle formulaΘcrit= sine-1 (nr/ni) = invsine (nr/ni)
  59. 59—

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Fichas sobre Physics Unit 4- waves, creado por Adeline Göttle el 11/10/2022.
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