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reflection
light hitting something and the rays ābouncingā reflecting back to our eyes
What are the two important parts of glass? What is their purpose?
light rays pass through the front transparent glass and then hit the reflection layer (silver/aluminum) behind it, causing the rays to bounce back to our eyes (causes us to see the reflection)
Light Ray
electromagnetic waves - carry energy / travels
explain how light rays travel and transferrs
electromagnetic waves - carry energy / travels through a vaccum
light energy transferred through radiation
(transfer of heat) what is the difference between conduction and convection? give examples
conduction: direct contact with solids - transfer between adjacent molecules
ex. heating a pan on a stove
convection: movement of a fluid when heated fluid is caused to move away from heat source - carrying energy happens because of density (liquid heated > rises >cools > falls)
ex. lava lamps, burning paper, cooking beans in liquid,
(transfer of heat) what is radiation?
no physical contact - energy coming off of a source - travels through space at speed of light
ex. heating hands near a fire
types of light emissions
Luminous: an object that emits/produces its own light (eg. sun)
Non-luminous: an object that does not produce its own light and is visible due to reflected light (eg. a tree)
Geometric Optics
light rays to determine how light behaves when hitting objects
give an example of transparent, translucent, and opaque
transparent: air, water, clear glass
translucent: thin paper, vegetable oil
opaque: wood, concrete, floors
(model of light)
What are the 2 rays and line? Define all of them
Normal: line perpendicular to where ray of light meets
Incident ray (ray coming in): ray traveling from source to surface
reflected ray (ray bouncing off): begins at point where incident ray + normal meets
(model of light)
What are the two angles? Define all of them
angle of incidence: between normal and incident ray
angle of reflection: between normal and reflected ray
What is specular reaction and diffuse reaction?
specular: All angles of incident for light rays identical (light hits SMOOTH surface) - all angles of reflection identical
diffuse: When parallel incident rays are reflected off of an IRREGULAR surface - all angles of reflection different
Name all the ways of production of light. what are the ones that are natural and the ones that are man-made?
NATURAL: Bioluinescence, trioluminescence
MAN-MADE: luminous, incondescene, electric discharge, phosphorescence, fluorescence, LED, Chemillumiescence,
What are the two laws in Ray Model of Light?
incident ray, reflection ray, normal to the surface of the mirror - lie on same plane
angle of reflection = angle of incidence
What are the similarities and differences of Phosphorus and Fluorescent light?
both result from absorption of ultraviolet light
Phosphorus : - emission over period of time
fluorescent : - IMMEDIETE emission of visible light
MEDIUM
physical substance through which energy is transferred (convection / conduction)
explain LANTA
wave length - the distance waves travel within a period
from L ā R: Lanta gets shorter
what is electromagnetic spectrum?
light listed according to diff energy levels
what did maxwell predict about electromagnetic waves?
Electricity + magnesium work together - forms a chain travelling through space
the resulting electromagnetic waves doesnāt require a medium for transmission - travels speed of light
Why is studying electromagnetic waves better than studying only visible light?
Most things in the universe arenāt in the electromagnetic range to be visible to us (radio waves, microwave, TV)
bioluminescence and triboluminescence - Give examples
bioluminescence : produced in living creatures
triboluminescence : light emitted because of friction with minerals / crystals
Does fluorescent brighteners in cleaners make clothes cleaner? explain
fluorescent brighteners in cleaners do not make clothes cleaner
the brighteners absorb UV light, producing visible light and making clothes brighter
What are some problems and dangers with fluorescent lights?
fluorescent light contains mercury (non-biodegradable)
Why are incandescent bulbs ineffective? Why are fluorescent bulbs better?
Incandescent bulbs are ineffective because they are constantly at a high temperature in order to produce light - it cannot be on for a long time or else it will overheat - canāt produce that much electricity / uses more energy + less reliable
Why are LED lights more effective than fluorescent bulbs?
LED lights use a majority of their energy focused on producing light (not much energy wasted and therefore can last longer) - unlike fluorescent bulbs, it has no mercury, so more biodegradable.
How do fluorescent lights work? What is inside it? What happens when it is turned on?
both electric discharge and fluorescence
tube filled with mercury vapour - emits UV light
tube has fluorescent inner surface
when on:
electric current causes mercury to emit UV light
UV hits fluorescent inner surface - produces visible light
How do you make light using electric discharge?
passing an electric current through a gas ā causes gas to GLOW
(ex. neon sign)
What si luminous and non-luminous light
Drawing Ray Diagrams for Concave Mirrors (diagrams)
(1): Locate theĀ Principal Axis \n (2): Locate theĀ Centre of Curvature "C" \n (3): Locate theĀ Vertex \n (4): Locate theĀ Focal Point/Focus (F) - half the distance of the radius, half way between the Centre of Curvature and the Vertex. \n (5): Determine theĀ Focal length (f) - distance between the vertex and the focal point
what does SALT stand for (give examples)
S- size (small,large,same)
A- attitude (up,invert)
L- location (behind mirror, betwn C-F, etc)
T- type (virtual, real)
(Concave mirrors-SALT) How do you describe an object when it is
-BEYOND C
S- Smaller
A- Inverted
L - Between C & F
T - Real
(Concave mirrors-SALT) How do you describe an object when it is
-On C
S- Same size
A- Inverted
L - on C
T - Real
(Concave mirrors-SALT) How do you describe an object when it is
-Between C and F
S- bigger
A- Inverted
L - beyond C
T - Real
(Concave mirrors-SALT) How do you describe an object when it is
-on the FOCAL POINT
NO IMAGE
(Concave mirrors-SALT) How do you describe an object when it is
-Object between F and MIRROR
S- bigger
A- upright
L - behind the mirror
T - Virtual
(concave) What happens with the light rays when the object is Beyond C, At C, or between C-F
1 - incident rays that travel perpendicular to the principal axis reflect off mirror - reflective rays go through FOCUS
2- incident ray travel through focus - reflective rays parallel to principal axis
-all real all inverted
(concave) What happens with the light rays when the object is AT F
NO IMG
(concave) What happens with the light rays when the object is betwn F and Mirror
S- bigger
A- upright
L - behind the mirror
T - Virtual
what is the relationship between TYPE and ATTITUDE of an image
Real - Inverted
Virtual - Upright
what is the difference between PLANE, CONCAVE and CONVEX mirrors
PLANE: - virtual imgs - reflected image same size
CONCAVE: - reflective rays converge on a point - reflected image magnified
CONVEX: - light rays DIVERGE - virtual imgs - reflected image smaller
list these electromagnetic waves from lowest to highest energy :
microwaves, gamma rays, infrared light, visible (white) light, radio waves, X-ray
radio waves < microwaves < infrared < visible (white) < ultraviolet < x-ray < gamma ray
SALT for Plane mirrors
S - same size
A - inverted
L - behind mirror
T - virtual
ray diagram for convex mirror (and attributes)
S- smaller
A- upright
L- between F-V(mirror)
T- virtual
7 distinct colours in order of lowest to highest energy
Red \n Orange \n Yellow \n Green \n Blue \n Indigo \n Violet
Note 
Flashcard (48)