Science Unit 2 - Chapter 11 - copy
What is light?
sunlight is the energy that makes life possible of earth. Earth captures only a tiny of a fraction of the sun's light. Sunlight is what suports life on earth.
What are the three properties of light?
1. Light travels at very high speeds (3.0 10 to the power of 8 m/s.)
2. Light travels in straight lines
3. Light does not require a median.
What are photons?
packets of light energy
what is a medium?
any physical subtance through which energy is transferred. (copper pot when it conducts heat)
How is light energy transferred?
Through radiation
What is radiation?
method of energy transfer that does not requre a medium, because the light travels at the speeds of light.
Who is James Maxwell? What did he do?
He predicted the exsistance of electromagnetic waves.
What are electromagnetic waves?
A wave that has both electric and magnetic parts, does not require a median and travels at the speed of light.
What is the elctromagnatic spectrum?
The electromagnatic spectrum shows the classification of electromagnetic waves by energy
What is the order of electrro magnetic waves
radio waves, microwaves, infared lights, visable light, ultraviolet light, x-rays, gamma rays
low energy has what kind of wave length
long wave length
high energy means what kind of wave length
short wave length
What is luminous and non-lumnious light?
Luminous - Prodcues its own light (sun,phone,projecter)
Non-Luminious - Does not produce its own light, seen by reflecting of light (chair,pencil)
What are the 7 diffrent ways light is produced?
1. Lights from Incandescence
2. Lights from Electric Discharge
3. Lights from Phosphorescence
4. Lights from fluresecence
5. Lights from Chemiluminiescence
6. Lights from Bioluminoescence
7. Lights from Triboluminscence
What is lights from incandesscence?
-production of light as a result of a high temp
-Filament in the incandescence ligh bulb burns and infared light is shown
-Only 5-10% of the electricty is actually used to create light
-Amber from fires, metal stove in a spiral
What is lights from Electric Discharge?
- Is the process of producing light by passing an eelctric current through a gas
- Neon gas produces red colour, helium produces gold coloured glow, argon a pale violet blue, and krypton a greyish off-white
- lighting signs on stores
What is light from Phosphorescence
- Is the process of producing light by absortion of ultra violet light, resulting in the emission of visable light over a period of time
- Ex. Glow in the dark sticks
What is light from Flurescence
- Is the immediate emission of visable light, as a result of the absortion of ultra violet light
- Villed with mercury vapor (Hg) and the inner surface is coated with a flurescent material.
- electricy causes the mercury atoms to emit ultra violet light, which strikes the fluoresecent material.
What is compact flurescence light (CFL)?
- Provides the same light output as an equivalent incandescent bulb, using less electricty
- Contain mercury vapour which is hazourdous
What is lights from Chemiluminescence?
- Is the direct produciton of light as the result of a chemical reation with a little or no heat produced
- Ex: glow-worms, fireflies
What is light from Triboluminescence?
- is the production of light from friction as a result of scratching or rubbing certain crystals
3 properties of a laser
1. Pure in colour
2. Very intense
3. Concentrated into one narrow beam
What does a laser produce?
Produces electromagnetic waves at exactly the same energy level as incandescent bulbs
What is a light ray?
A line on a diagram representing the direction and path it is traveling in
What is an Incident light
Is emitted from a source that strikes on a object
What are geometric optics
involvesj the use of light rays to determain how light behaves when it strikes an object
What is transparent material?
transmits all or almost incident light, allowing objectgs to be seen clearly. Ex: Clear Glass
What is a translucent?
material transmits same incident light but absorbs or reflects the rest. Ex: frosted Glass
What is an Opaque object?
object that does not transmit any incident light, all light is absorbed or reflected. Ex: Textbook
What is an Image?
is a reproduction of an object through the use of light
What is a mirror
is any polished surface reflecting an image
What is a reflection
Is the bouncing back of light from a surface
Mirrors consistant of what 2 parts
1. Sheet of glass (cleanable) 2. Thin layer of reflecting silver or aluminum
What type of material is Mirror
Opaque
What type of mirros are plane mirros
flat mirrors
What is an incident ray
is the incoming ray that strikes the surface of the mirror
What is an reflected ray
ray that bounces off a reflective surface
What is a normal
is a perpendicular dotted line to a mirorr surface
What is the angle of Incidence
is the angle between the incident ray and the normal
What is the angle of reflection
is the angle between the reflected ray and the normal
What are the two laws of reflection
1. The angle of incidence equals the angle of reflection
2. The incident ray, the reflected ray and the normal all lie in the same place --> flat surface
What is specular reflection?
is the reflection of light off a smooth surface --> reflection off a plane mirror
What is Diffuse reflection
is a reflection of light off on irregular or dull surface. ---> the reflected rays are scatterd all over the place.
What is a virtual image:
is an image formed by light coming from an apparent light source and not from the actual image location
What are the characteristics of an image in a plane mirror?
- The image is upright but flupped horizontally.
- The word science would be reversed
What is the acronym for S.A.L.T.
Size: of image compared to the object (larger, smaler or same size)
Attitude: of image (image vertical orientation: upright or inverted)
Location: of image ( infront, or behind the mirror, and at what distance)
Type: of image (real or virtual)
What is areal image
a real image is an imaged formed when light is actually arriving at the image location
What are the 2 types of curved mirrors?
Concave Mirrors (converging) - is a mirror shaped like part of a sphere, with a reflective outer surface.
Convec Mirrors (diverging) - is a mirror shapped like part of the surface of a sphere, with a reflective outer surface
Concave mirror
A mirror in which the reflecting surface is caved in.
Ex: inside of spoon, used in headlights, makeup mirror.
Terms for Curved Mirros
1. (Centre of Curvature CC) - the centre point of a sphere thatforms the curved mirrors.
2. (Principal Axis PA) - a horizntal line (90d) from the centre of curvature to the centre of the mirror
3. (Vertex V) - The point when the principal axis meats the convex mirror
4. (Focal Point F) - A point half-way between the centre of curvature and the vertex where a parallel light rays come tg.
5. (Focal Length f) - The distance between the focal point and the vertex)
What are convex Mirrors
is a mirror in which the reflecting surface faces out (ticks outside)