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Flashcards

waves

lizabeth rawson Physics GCSE English 81 cards

Cards in this deck (81)

  1. 1what is the amplitude of a wavemaximum displacement of a point on the wave from its undisturbed position, the height of a peak / trough
  2. 2what is the wavelength of a wavedistance between the same point on two adjacent waves, eg between two peaks
  3. 3what is the frequency of a wavenumber of complete waves passing a certain point per second (Hz)
  4. 4give equation for a periodperiod (S) = 1 / frequency (Hz)
  5. 5what are transverse waves and give examplesoscillations that are perpendicular to the direction of energy transfer, most waves are transverse, electromagnetic waves, ripples and waves in a water, a wave on a string
  6. 6what are longitudinal waves and give examplesthe oscillation are parallel to the direction of the energy transfer, eg sound waves in air, ultrasound and shock waves
  7. 7give the definition and equation for wave speedthe speed at which energy is being transferred: wave speed (m/s) = frequency (Hz) x wavelength (m)
  8. 8all EM waves are _________ waves, that transfer energy from a ______ to an ________. they all travel the same speed through air or a _____,transverse, source, absorber, vacum
  9. 9name all the EM waves from biggest to smallest wavelengthradio waves, micro waves, infra red, visible light, ultra violet, x-rays, gamma rays
  10. 10name all the EM waves from biggest to smallest frequencygamma rays, x-rays, ultra violet, visible light, infra red, micro waves, radio waves
  11. 11name the wavelengths for all the EM wavesradio waves 1 - 10⁴ m, micro waves 10-² m, infra red 10-⁵ m, visible light 10-⁷m, ultra violet 10-⁸m, x-rays 10-¹⁰ m, gamma rays 10-¹⁵ m
  12. 12how are EM waves generated?by changes in atoms and their nuclei
  13. 13what is refractionwhen a wave crosses a boundary between materials at an angle, and it changes direction
  14. 14if a wave crosses a boundary and slows down, it will bend _______ the normal. if it crosses a boundary and speeds up, it will bend ____ from the normaltowards, away
  15. 15true or false, the wavelength of a wave will change when it is refracted, but the frequency stays the sametrue
  16. 16what happens when a wave is travelling along the normalthe speed is affected but it is not refracted
  17. 17what does optical density meanmeasure of how quickly light can travel through it. the higher the optical density, the slower light waves travel through it
  18. 18how do you construct a ray diagram for a refracted light ray?draw the boundary, and draw the normal as a dotted line. draw an incident ray that meets the boundary at the normal. the angle between the ray and the normal i the angle of incidence. draw the refracted ray on the other side.
  19. 19if a second material is more optically dense, then the angle of refraction is ______ than the angle of incidence. if it is less optically dense, the angle of refraction is ______ than the angle of incidencesmaller, larger
  20. 20give uses for microwavescommunication to and from satellites, satellite tv, heating up food
  21. 21how does satellite tv workthe signal from a transmitter is transmitted into space where it is picked up by the satellite receiver dish orbiting thousands of km above the earth. the satellite transmits the signal back to earth in a different direction where it is received by a satellite dish on the ground, there is a slight delay because of the long distance.
  22. 22how do microwaves workthe microwaves penetrate a few cm into the food before being absorbed and transferring the energy that their carrying into the water molecules causing the water to heat up. the water molecules then transfer this energy to the rest of the food molecules to cook the food quickly
  23. 23what are infra red waves used ininfra red cameras, cooking food, electric heaters
  24. 24how does an infra red camera workthey detect the IR radiation and turn them into an electrical signal to be displayed on a screen as a picture
  25. 25give a use of visible light rays and how does it workfibre optic cables, to transmit data, which are thin glass or plastic fibres to carry data over long distances as pulses of visible light, they work using reflection, the light rays bouncing back and forth. it is safer because the light is contained in the fibre
  26. 26give uses for ultraviolet radiationsecurity pens to mark property, under uv light the ink will fluoresce, cosmetic tanning beds.
  27. 27give uses of x raysto look at broken bones
  28. 28give uses of gamma raysradiotherapy (medical tracer)
  29. 29what can happen when a waves arrive at a boundary?they can be absorbed, transmitted, or reflected
  30. 30what is the angle of incidence equal tothe angle of reflection
  31. 31how do light waves reflect on a smooth surfaceit is specular reflection, they are all reflected in the same direction
  32. 32how do light waves reflect on a rough surfacediffuse reflection, reflected waves are a scattered in many directions
  33. 33why don't you get a clear reflection on a rough surface?because since the normal if different for each ray of light, it is all diffused and so it is not reflected clearly
  34. 34what are EM waves made up ofoscillating electric and magnetic fields
  35. 35what are alternating currents made up ofoscillating charges, as the charges oscillate, they produce oscillating electric and magnetic fields (EM waves)
  36. 36how do you produce a radio waveusing an alternating current in an electrical circuit. the object in which charges (electrons) oscillate to create the radio waves is called a transmitter.
  37. 37what are longer radio waves used for, and what makes them good for this functionlong wavelengths (1-10km)means they can diffract around the curved surface of the earth to other places in the world, as well as diffract around hills and tunnels. they are used for communication.
  38. 38what are longer radio waves used for, and what makes them good for this function10m-100m, they can be received at long distances by reflecting of the ionosphere. Bluetooth uses these as well as TV and FM radio
  39. 39what affect do low frequency EM waves have on the body?pass through soft tissue without being absorbed
  40. 40what affect do high frequency EM waves have on the body?transfer lots of energy so can cause lots of damage
  41. 41what affect does UV radiation have on the body?damages surface cells, sunburn, premature skin ageing, blindness, increased risk of skin cancer
  42. 42what affects do x-rays and gamma rays have on the body?ionising, can cause gene mutation or cell destruction and cancer
  43. 43what is radiation dosemeasured in Sv, measure of the risk of harm from the body being exposed to radiation
  44. 44CT scans uses _____ and a _____to build up a picture of the inside of a patient's body,x-rays, computer
  45. 45what is a concave lensa lens that curves inwards, it causes parallel light rays to diverge (spread out)
  46. 46what are concave and convex lenses?convex is thickest in the middle, used for long sighted (hypermetropia) makes parallel light rays converge so that the rays are focussed on the retina. concave is thickest at either end, for short sightedness (mytopia) and causes parallel rays to diverge so that the rays are focussed on the retina
  47. 47add diagrams on the convex and concave kensesdo it
  48. 48what is the speed of light3x10*8
  49. 49what is a refractive indexhow fast light travels through a material
  50. 50add diagrams on ray diagrams through convexlens
  51. 51magnification =image height / object height
  52. 52what is the wavelength range for visible lightviolet 400nm, to red 700nm
  53. 53what is an opaque objectan object that does not transmit light, they absorb and reflect instead
  54. 54what is the colour of an objectthe most strongly reflected wavelength, the rest of the wavelengths are absorbed.
  55. 55a red apple reflects _____ light, a black object _____ all light, a white object ________ all lightred, absorbs, reflects
  56. 56what colours mix to give magenta, yellow, and cyanred + blue = magenta
    blue + green = cyan
    green + red = yellow
  57. 57what makes objects transparent or translucentthey transmit most light waves
  58. 58how does a colour filter workthey only transmit certain colours/wavelengths, the rest is absorbed. if the colour isn't primary, it lets through the wavelengths of that colour and wavelengths of the primary colour that mix to get it
  59. 59what would happen is white light was shone on a red hat through a blue colour filterit would appear black because the red wavelengths would be absorbed by the blue colour filter
  60. 60where and when is infrared radiation emitted and absorbedcontinually of the surface of an object
  61. 61if an object is at a constant temperature, it is absorbing at the ____ rate as it is emitting itsame
  62. 62what is a leslie cube?a hollow watertight metal cube whose four vertical surfaces have different finishes.
  63. 63what is a perfect black bodyobject that absorbs all of the radiation that hits it, none reflected or transmitted
  64. 64what does the intensity and distribution of the wavelengths emitted depend on/the object's temperature, and the power per unit area
  65. 65what are sound waves (longitudinal waves) caused byvibrating objects
  66. 66true or false, sound waves travel faster in a liquid than a soilidfalse, they travel faster in solids because there are more frequent vibrations in the closer particles
  67. 67why can't sound waves travel in a vacuum?no particles to move or vibrate
  68. 68how do you measure the speed on a piece of stringmake a standing wave, control the frequency with a frequency generator. measure the number of complete waves, and the frequency and multiply them together
  69. 69how do you hear sound?sound waves make your eardrum vibrate, the cochlea turns these vibrations into electrical signals that are then sent to your brain
  70. 70what is the hearing range of the human ear20Hz - 20kHz
  71. 71sound waves can be _________ by hard surfaces, thats what ______ arereflected, echoes
  72. 72what is ultrasound?frequencies above 20 000 Hz
  73. 73what is partial reflectionwhen a wave passes from one medium to another, some of the wave is reflected off the boundary between the two media, and some is transmitted
  74. 74how is ultrasound used in medical imagingultrasound waves (produced and received by a transmitter/receiver) can pass through the body, but when they reach a boundary some is reflected back and detected, this can produce a video image of a foetus.
  75. 75how is ultrasound used in finding flaws in materialsif there is a flaw in an object, the ultrasound wave is reflected back before they reach the end, and recorded as a image
  76. 76what happens when an earthquake occurs?it produces seismic waves, which we can detect using seismometers, which work out the time it takes or the shock waves to reach each seismometer.
  77. 77what are P wavesseismic wave, P waves are longitudinal, and can travel through solids and liquids, and travel faster than S waves, they can pass through the solid inner core, liquid outer core, and the mantle.
  78. 78what are S wavesseismic waves, transverse and can't travel through liquids and they are slower than P waves, they can pass through the mantle but not the core
  79. 79insert diagramson p waves and s waves
  80. 80a convex lenses produces an upright/inverted real/virtual and smaller/bigger image than the originalupright, virtual, smaller
  81. 81insert table about convex lenseproperties of image etc

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GCSE Physics (paper 2) Flashcards on waves , created by lizabeth rawson on 02/03/2020.
Created by
lizabeth rawson · Mar 2020
Updated
Mar 16, 2020
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