Chap 5 - reflection, refraction, diffraction, critical, total internal reflection, light drawing, lens Flashcards

1
Q

define refraction

A

-change in direction of wave as they pass through different mediums

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2
Q

define reflection

A

-wave bounces off a plane surface at the same angle it came from

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3
Q

define diffraction

A

-bending at the ends of a wave as it passes through a narrow gap

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4
Q

define plane surface

A

2D flat surface

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5
Q

define normal

A

perpendicular line from the surface

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6
Q

does the wave speed, frequency and wavelength change in reflection

A

no for all

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7
Q

rays in reflection

A

-incident
-reflected

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8
Q

rays in refraction in order

A

-incident
-refracted

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9
Q

is there a normal in refraction and reflection

A

yes

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10
Q

does the wave speed, frequency and wavelength change in refraction

A
  • f is constant
    -v & λ changes
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11
Q

what happens when incident ray is 0 (at normal) for reflection & refraction

A

-no reflection/ refraction happens

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12
Q

does the wave speed, frequency and wavelength change in diffraction

A

no change to all

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13
Q

how does size of wave length affect how wave is diffracted

A

-short wave length, less diffraction

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14
Q

virtual lines in reflection

A

-distance from obj to mirror is same as distance from virtual image to mirror
-virtual image lines are dotted
-the reflected ray and dotted lines meet

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15
Q

change in v & λ from deep to shallow water

A

-deep - shallow = v & λ decrease
-f is constant

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16
Q

properties of light

A

-form of radiation
-travels in straight lines
-transfers energy
-travels as waves
-travels through vacuum
-3 x 10^8 m/s

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17
Q

define luminous & eg

A

-produce light
-sun, lamp, torch

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18
Q

define non- luminous & eg

A

-reflect light
-moon, pen, book …

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19
Q

diff of light in white & black

A

-white reflects all colours
-black absorbs all colours

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20
Q

experiment to know light travels in a straight line

A

-light through a hole in a dark room
-if light not travel in straight lines = room would be lit

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21
Q

define monochromatic light

A

-light of a single λ & 1 colour

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22
Q

why are some colours visible

A

-the colour is reflected while the other colours are absorbed

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23
Q

refraction from less dense medium to more dense medium ( n )

A

-LDTN
-decrease speed - towards normal

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24
Q

refraction from more dense medium from less dense medium ( n )

A

-MDAN
-increase speed - away from normal

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25
Q

how to show a surface is a mirror

A

-hatched lines behind the line
-all rays behind mirror are virtual

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26
Q

define critical angle

A

-when the refracted ray is perpendicular to normal
-varies with medium

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27
Q

define total internal reflection

A

-when incident angle is greater than critical angle, there is not refraction - only reflection
-in transparent medium
- has to be from more n to less n & incident angle is more than C

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28
Q

how is diffraction affected by size of gap

A

bigger gap = decreased diffraction

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29
Q

why do radio waves diffract more than light waves

A

they have longer wavelengths

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30
Q

what happens when incident angle is more than critical angle

A

-total internal reflection
-no refraction - only reflection

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31
Q

v from light blue medium - dark blue medium

A

-slow down

32
Q

law of reflection

A
  • incident angle = reflected angle
  • rays & normal lie on the same plane
33
Q

Snell’s law

A

n = sin ( i angle ) / sin( r angle )

34
Q

3 formulas to find refractive index

A
  • n = sin ( i angle ) / sin ( r angle )
  • n = 1/ sin ( C )
  • n = c / speed of light in medium
    ( use sin^-1 if needed to convert to angle)
35
Q

note: C = critical angle, c = 3 x 10^8 m/s (speed of light in vacuum )

A
36
Q

what happens if a barrier is put at the end of a ripple tank

A
  • waves are reflected
  • change in wave front
37
Q

what happens if a transparent barrier is put in ripple tank

A

-waves are reflected or refracted

38
Q

what happens if a barrier with a gap is put in a ripple tank

A

-waves are diffracted

39
Q

how does gap size affect diffraction

A

-f is constant
-small gap = arc
-big gap = unchanged with edge bent

40
Q

define virtual image

A

image that cannot be captured on a screen
-laterally inverted
-upright
-virtual

41
Q

define real image

A

image than can be captured on a screen

42
Q

define image

A

copy of a real object

43
Q

types of lenes

A

-convex - converging lens - rays come to 1 particular point
-concave - diverging lens - rays scatter

44
Q

how is the focal length & principle focus diff in converging & diverging lens

A

converging - principle focus & focal length after lens
diverging - principle focus & focal length before lens - lines to principle focus are dotted

45
Q

note: refractive index is constant

A
46
Q

types of reflection & their causes

A

-regular reflection - plain surface
-diffuse reflection (scattered rays) - uneven surface

47
Q

characteristics of plain mirror

A

-upright
-virtual
-laterally inverted
-same size as object

48
Q

stages in endoscopy

A

-light passes through a bundle optical fibers in patients stomach
-reflected light passes through second bundles of optical fibers
-inside of stomach reflect light
-optical fibers take light to eye piece
-doctor can see through eye pieces

49
Q

what happens when 2 mirrors are perpendicular to each other

A
  • a laterally inverted C shape
    -all angles are same size
50
Q

note: your right is the same as the right in the mirror

A
51
Q

how to find distance of object to image

A

distance from image to mirror x 2

52
Q

note: only convex lens produce real images

A
53
Q

word, symbol & units for magnification formula

A

-image distance from optic center/ obj distance from optic center
-no units & symbols

54
Q

types of magnification

A
  • ( + ) - image is larger than obj
  • ( - )- image is smaller than obj
55
Q

examples of magnification

A

-magnifying glass
-microscope

56
Q

requirement for magnification

A

obj must be closer to lens than principle focus

57
Q

word, symbol & units for power of lens formula

A
  • 1/ focal length
  • P = 1/ f
    P = m^-1
    f = m
    -positive for convex lens
    -negative for concave lens
58
Q

how is converging affected by focal length

A

shorter focal length, more converging

59
Q

drawing for convex lens for image beyond focal point 1 (f1) - real image

A

-obj on left side
-ray 1 parallel to principle axis until lens and bends to f1
-ray 2 passes through optic center of lens and meets ray 1

60
Q

drawing for convex lens for image before and at focal point 1 (f1) - virtual image

A

-obj on left side
-ray 1 parallel to principle axis until lens and bends to f1
-ray 2 passes through optic center of lens
-if obj > f, rays meet at obj side
-if obj = f, rays don’t meet - image is not formed

61
Q

-properties of image at u>2f
-example
-image position

A

-real
-inverted
-diminished
-camera & eye
-image position: f<u<2f

62
Q

-properties of image at u=2f
-example
-image position

A

-real
-inverted
-same size
-photocopier
-image position: 2f

63
Q

-properties of image at f<u<2f
-example
-image position

A

-real
-inverted
-enlarged
-projector
-image position: >2f

64
Q

-properties of image at u=f
-example
-image position

A

-virtual
-upright
-enlarged
-spotlight
-image position: infinity

65
Q

-properties of image at u<f
-example
-image position

A

-virtual
-upright
-enlarged
-magnifying glass
-image position: same side as obj

66
Q

-properties of image at u<f
-image position

A

-real
-inverted
-highly diminished
-image position:

67
Q

note: refractive index cannot be less than 1

A
68
Q

what refractive index do you use depending on medium

A

-L - M : n
-M - L: 1/n
-check is ans is sensible

69
Q

what must angle r with angle i depending on medium

A

-L - M : r < i
-M - L: r > i

70
Q

note: erect = upright

A
71
Q

define principle axis

A

line perpendicular to lens which passes through the optic center

72
Q

define focal point (principle focus)

A

point in principle axis where light rays are parallel to the principle axis coverage or appear to diverge from

73
Q

define focal length

A

distance between optical center and principle focus

74
Q

rules when drawing

A

1) ray parallel to principle axis & pass through principle focus
2) ray that passes focal point emerges parallel to optical axis on other side of lens
3) ray that passes through center of lens has no change

75
Q

what type of lens is the eye

A

convex

76
Q

how is a real image produced

A

by the actual intersection of rays projected on a screen

77
Q

how is a virtual image produced

A

by the apparent intersection of rays that cannot projected on a screen