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P3 revision

daniel upton Englisch 64 Karten

P3 revision

Karten in diesem Stapel (64)

  1. 1Name 5 properties of x-rays.They have a very short wavelength, the same as the diameter of an atom.
    Cause ionisation.
    They are absorbed by metal and bone. They are transmitted by soft tissue.
    They affect a photographic film in the same way as light
  2. 2Give examples of x-ray medical uses.CT scans, bone fractures, dental
    problems and killing cancer cells.
  3. 3What precautions should be taken when using x-rays?The machine should be used as little as needed when doing a scan. The radiographer should stand behind a screen or leave the room so they aren't exposed to any radiation.
  4. 4What is the hearing range of a human being?20-20,000 Hz
  5. 5define an ultrasound wave.A wave of sound with frequency greater then 20,000 Hz.
  6. 6When are ultrasound waves partially reflected?At the boundary between two different media.
  7. 7What can the time taken for reflections of ultrasound waves to reach a detector be used for?How far away the boundary is.
  8. 8Give examples of medical uses of ultrasound waves.pre-natal scanning and the scanning and removal of kidney stones.
  9. 9What is refraction?Refraction is the change of direction of light as it passes from one medium to another.
  10. 10What does a lens do?A lens forms an image by refracting light.
  11. 11In a convex or converging lens what happens to the parallel rays of light?Parallel rays of light are brought to a focus at the principal focus.
  12. 12What is the focal length?The distance from the lens to the principal
    focus is called the focal length.
  13. 13What is the nature of an image defined by?Its size relative to the object, whether it is upright or inverted relative to the object and whether it is real or virtual.
  14. 14What is the effect on the image if the object is moved at different distances from the converging lens?What is the effect on the image if the object is moved at different distances from the converging lens?
  15. 15What lens is used in a magnifying glassConverging
  16. 16What is the nature of an image produced by a diverging lensDiverging lenses always produce images that are virtual, upright and diminished (smaller).
  17. 17—
  18. 18What is the function of the Cornea?Focusing light by a fixed amount.
  19. 19What is the function of the iris?To control the size of the pupil, controlling the amount of light that goes to the retina.
  20. 20What is the function of the Ciliary muscleTo control the shape of the lens using the suspensory ligaments to change how light is being focused onto the retina.
  21. 21What is the purpose of the lens?To focus the light entering the eye by a varying amount depending on it's shape.
  22. 22What is the purpose of the pupil?To control how much light hits the retina.
  23. 23What problem causes long sight?The eyeball being too short, or the eye lens being unable to focus.
  24. 24What lens is used to fix long sight?Converging
  25. 25What problem causes short sight?The eyeball being too long, or the eye lens being unable to focus.
  26. 26What lens is used to fix short sight?Diverging
  27. 27What is the range of vision?25 cm to infinity.
  28. 28What is the film or the CCDs in cameras equivalent to in an eye?The retina.
  29. 29What is the power of a converging lens?Positive
  30. 30What is the power of a diverging lensnegative
  31. 31What is the focal length of a lens determined by?■ the refractive index of the material which the lens is made from.
    ■ the curvature of the two surfaces of the lens.
  32. 32What is the relation between refractive index and flatness of a lens?The greater the refractive index, the flatter the lens.
  33. 33What does the relation between refractive index and flatness of a lens mean in terms of manufacturing?Lenses can be manufactured thinner.
  34. 34What can optical fibres be used for?Sending visible light?
  35. 35What is an example of, optical fibres using visible light?The endoscope for internal imaging.
  36. 36What can a laser be used for?Cutting, cauterising and burning.
  37. 37What is the centre of mass of an object?Point at which the mass of the object may be thought to be concentrated.
  38. 38If freely suspended the centre of mass will be directly below what?The point of suspension
  39. 39In a symmetrical object the centre of mass is along the axis of _____________symmetry
  40. 40In the equation: 1 T =--- F What is the units for F and TT = s
    F = Hz
  41. 41What is the turning effect of a force called?The moment
  42. 42In the equation M = F x D What are the units for each letterM = Nm
    F = N
    D = m
  43. 43If an object isn't turning what two forces must be in balanceThe total anticlockwise moment and the total clockwise moment
  44. 44If the line of action exceeds the base on an object what will happen?There will be a resultant moment and the body will tend to topple.
  45. 45What is the property of liquids that means they can be used for hydraulics?They are virtually incompressible
  46. 46The pressure in a liquid is spread _____________ and ____ ______ ________________Equally and in all directions
  47. 47A hydraulics system is a force what?A force multiplier
  48. 48In the equation F p = ----- A What are all the units for each letter?P = Pa or N/m squared
    F = N
    A = m squared
  49. 49When an object moves continuously in a circle it accelerates towards what?The centre
  50. 50What is the force called that acts on an object that is moving continuously in a circle called?centripetal force
  51. 51How can the centripetal force be increased■ the mass of the object increases
    ■ the speed of the object increases
    ■ the radius of the circle decreases.
  52. 52What has to flow through a wire for a magnetic field to be produced?current
  53. 53In Flemmings left hand rule what goes on the fingers and thumb?Thumb is movement
    Index finger is for magnetic field
    middle finger for current
  54. 54In the motor effect what is the movement of the wires if the south magnet is on the left and the north is on the right and the current is moving left to right?The left side moves up and the right side moves down
  55. 55Why does the motor effect work?The magnetic field produced from the wire interacts with the permanent magnetic field produced by the magnet causing a force on the wire making it move
  56. 56How can you increase the size of the force in the motor effect?■ increasing the strength of the magnetic field
    ■ increasing the size of the current.
  57. 57In the motor effect what part of the wire will not experience a force?The part that is parallel to the magnetic field.
  58. 58What two things reverse the direction of the force in the motor effect?if either the direction of the current or the direction of the magnetic field is reversed
  59. 59if an electrical conductor cuts through a magnetic field what is induced across over both ends on the conductor?A potential difference
  60. 60Describe a soft iron core transformer.Describe a soft iron core transformer.
  61. 61How does a soft iron core transformer work?An alternating current in the primary coil produces a changing magnetic field in the iron core and hence in the secondary coil. This induces an alternating potential difference across the ends of the secondary coil.
  62. 62In a step up transformer is the P.D. greater across the primary or secondary coil?secondary
  63. 63In a step down transformer is the P.D. greater across the primary or secondary coil?primary
  64. 64What is the frequency that switch mode transformers operate between?50 kHz and 200 kHz

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Karteikarten am P3 revision, erstellt von daniel upton am 08/05/2017.
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daniel upton
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