Light and Optical Systems Flashcards
name the 2 types of light
natural (sun, fire, bioluminescent)
artificial (LED, fluorescent, incandescent, phosphorescenct, chemiluminescent
ray model of light
(an explanation based on observation of how light behaves)
light travels in straight lines
a “ray” is a straight line that represents the path of a beam of light
law of reflection
the angle of incident is the same as the angle of reflection and same with the incident ray and reflection ray
angle of incidence = angle of reflection
Two characteristics that make telescopes useful for observing the skies are their ability to:
a) separate and magnify light
b) magnify and collect light
c) collect and separate light
d) magnify and clarify light
b) magnify and collect light
The difference between a convex lens and a concave lens is:
a) convex lenses are thicker in the middle
b) concave lenses are thicker in the middle
c) convex lenses spread out light rays
d) concave lenses concentrate the light
a) convex lenses are thicker in the middle
plane mirror
reflection
same size, same distance, virtual image
A plane mirror has a(n):
a) curved surface
b) focal point
c) ability to bend light
d) flat surface
d) flat surface
A concave mirror reflects rays so that they:
a) converge to focal point
b) diverge and spread out
c) reflect and converge to a focal point
d) reflect and diverge or spread out
c) reflect and converge to a focal point
name the 5 sources of light
fluorescent
incandescent
phosphorescent
chemiluminescent
bioluminescent
fluorescent light?
UV radiation
coating glows and produces light
more expensive and difficult to dispose of
phosphor coating and mercury vapor are toxic
ultraviolet light energy –> energy absorbed by particles –> visible light energy
incandescent light?
So hot it glows
(candle, light bulb)
electrical energy –> thermal energy –> visible light energy
phosphorescent light?
radiation
(inner surface of TV and computer screens)
chemiluminescent light?
chemical reactions
(glow sticks)
chemical energy –> visible light energy
bioluminescent light?
chemical reactions within animal bodies
(fungi, fireflies, fish)
LED
Light Emitting Diode
Electricity
very efficient
long lasting
expensive
Name 3 types of materials
Transparent - light passes through (air, water)
Translucent - some rays bounce back and some go through (paper)
Opaque - materials that totally block the light and cast shadows (books, desk)
luminous
produces (or emits) light
convex mirrors
convex: (lens curves outward)
small / far away
reflects rays so that they reflect and diverge or spread out
car mirror/securit
concave mirrors
concave: (lens curves inward)
big or upside down
(makeup mirror)
THE EYE: ciliary muscle
changes shape to focus
THE EYE: lens
focuses light
the more CONVEX (fat) the lens is, the more rays are refracted
THE EYE: iris
the coloured part
controls the amount of light
THE EYE: pupil
opening for light
THE EYE: cornea
helps focus
the transparent front part of the eye that covers the
iris, pupil, and anterior chamber
THE EYE: optic nerve
sends message to the brain
THE EYE: Sclera
protective outer layer
the white part
THE EYE: blind spot
the point where the optic nerve enters the retina
has no light-sensing cells
THE EYE: vitreous humour
keeps shape of eye, clear
THE EYE: aqueous humour
holds shape of front of eye
THE EYE: retina (including rods and cones)
light sensitive cells capture image
THE EYE: near-sighted
what type of lens corrects this?
the image falls short of the retina
vision corrected with concave lens
(eye has longer shape than normal eye)
THE EYE: far sighted
what type of lens corrects this?
the image falls behind the retina
vision corrected with convex lens
(eye has shorter shape than normal eye)
gamma rays
shortest wave length and highest frequency waves
(nuclear, radiation, cancer treatment)
x-rays
short wave length and
capable of penetrating solids
(electromagnetic radiation)
ultra-violet (UV) radiation
wavelengths of 200 nm beyond violet light
in the electromagnetic spectrum
causes tanning
nm = nanometer
visible light
wave length we can see
light we can see
infra-red
heat radiation
anything that is warmer than its surroundings emits infra-red rays
longer wave-length than visible
microwaves
longer wave-length than infrared
(microwaves, radar)
THE EYE: wavelength
distance from crest to crest or trough to trough
electromagnetic spectrum
Radio waves
Microwaves
Infrared waves
Visible light
Ultraviolet rays
X-rays
Gamma rays
frequency
number of waves that pass a point in one second
high frequency = short wavelength
low frequency = long wavelength
amplitude
height of the wave
EMR: electromagnetic radiation
visible light energy
radiant energy
refracting telescope
a telescope having a convex lens to collect and focus light from a distant object and an eyepiece lens to magnify the image
reflecting telescope
a telescope having a concave mirror to collect
rays of light from a distanct object
prisms in binoculars
.
remote sensing technology
getting information about an object without making physical contact
(such as the Hubble Space Telescope)
when looking at a fish tank you notice that your
goldfish is not where it appears to be
the apparent position of the fish is due to the fact that,
as light travels from the water to the air, it bends:
AWAY from the normal
