optics unit 1 test Flashcards
what is light?
visible light is an electromagnetic wave (electromagnetic spectrum, classified by energy)
2 ways to describe light
wave and particle
all waves travel at the speed of
3.00x10>8 m/s
higher frequency equal
higher energy
order of spectrum from slowest to fastest
radio waves
microwaves
infrared light
visible light (smallest section)
ultra violet light
x-rays
gamma rays
visible light is apart of the spectrum that can be seen by the human eye (T/F)
True
light released by the sun
UV (ultraviolet light) causes sunburns and reactions
light needs a medium to travel (T/F)
false
examples of radio waves
AM/FM radio
TV signals
cellphone communication
examples of radio waves
AM/FM radio
TV signals
cellphone communication
what type of light are:
remote controls
laser
physical therapy
infrared light
examples of visible light
human vision
concert lighting
rainbows
what type of light are:
microwave ovens
telecommunications
astronomy
microwaves
what is an example of all types of light except visible light?
astronomy
x-rays
medical imaging
security equipment
cancer treatment
what type of light are:
cancer treatment
product of some nuclear decay
Gamma rays
what region is visible light on the electromagnetic spectrum
380nm to about 750nm
relation between colour an speed of light
larger the number slower the wave length
lower the number faster the wave length
red = slow
purple = fast
8 ways light is produced
I Eat Pigs For Church Because They Love
incandescence
electric discharge
phosphorescence
fluorescence
chemiluminescence
bioluminescence
triboluminescence
LED’s
incandescence
light produced by something that has reached a high temp
(lava/fire)
cooler the object the redder it is
eventually
hotter object the bluer it is
glowing
incandescence light bulb
tungsten filament heats up with elec current and glows
electric discharge
light produced by elec current passing through gas
diff gasses produce different colours of light
elec discharge pattern of colours
glowing red
red deep orange
purple
blue
light blue/white
phosphorescence
light produced by chem phosphorus
these materials can store and absorb UV light energy
energy absorbed is released as lower energy visible light
diff materials = diff periods of time energy stored
fluorescence
the immediate admission of visible light as a result of UV light
have mercury atoms that release UV light when light hits fluorescent material visible light is created
(detergents contain fluorescent dyes)
chemiluminescence
direct production of light as the result of a chem reaction
with little or no heat produced
(glowsticks)
bioluminescence (think bio)
result of chem reactions within a living organism that releases visible light
(firefly) = produce an enzyme called luciferase that starts the reaction that produces light
triboluminescence (cheating person)
production of light when crystals are scratched crusted or rubbed
CaF2 and ZnS
LED’s
light Emiting diodes
produce light as a result of a one way current flowing through semi conductors
light travels in
straight lines
represented with an arrow on it showing direction of travel
what is the use of light rays to determine the path of light when it strikes objects
geometric optics
transparent
light completely passes through
translucent
some light passes through (absorb/reflects the rest)
opaque
no light passes through
(absorbs/reflects all light)
what is a mirror?
polished surface able to create an image
what is an image?
reproduction of an object using light
light hits the _____ and is ______ or ______ back, which allows for the creation of the _______
mirror
bounced
reflected
image
what are mirrors made out of?
clear glass and layer of film (piece of metal as backing)
incident ray
incoming ray that strikes a surface
reflected ray
bounces off reflected surface
the normal
perpendicular to mirror
angle of incidence
angle between incident ray and normal
angle of reflection
angle between reflected ray and normal
laws of reflection
- angle of incidence = angle of reflection
- incident rays, reflected ray , and the normal all line in the same plane
specular reflection
reflection of light off a smooth surface
diffuse reflection
reflection of light off of irregular or dull surface
SALT
S = size of image
A = attitude of image (upright/ inverted)
L = location of image
T = type of image (real/virtual)
shape of mirror results in
new type of image
concave mirrors
convergence: where light rays end up meeting at a specific point called the focus
concave mirrors diagram easy
1 parallel then through focus
2 center of curvature reflected back onto itself
3 through focus then parallel (opp of 1)
4 ray aimed at vertex following LOR (think normal mirror)
light behind C concave
(parallel through focus) (focus through parallel)
smaller
inverted
between C and F
real
light on C concave
same size
inverted
at C
real
light between C and F concave
larger
inverted
behind C
real
light on F concave
no image formed reflected rays are parallel
2nd line goes through vertex bc its on F
light in front of F concave
behind mirror
larger
upright
virtual
line through center of curvature to top of light source continues behind mirror
2nd line through vertex bc in front of F
convex mirrors
diverging light rays = spread apart on contact with mirror (always virtual and smaller images)
convex mirror diagram easy
1 parallel diverge off in line with focus
2 in line with C back onto itself
3. in line with focus then parallel (opp of 1)
what is C F and line
C = center of curvature
F = focus
line = principle axis/ normal
