Optics Unit review

Question 1

What are 4 properties of light?

Answer 1

1. light travels in straight lines
2. light travels VERY FAST - around 300,000 metres per second
3. light travel MUCH FASTER than sound
4. light is an electromagnetic wave

Question 2

Electromagnetic waves in order from longest wavelength to shortest wavelength

Answer 2

LONGEST

radio
Microwave
Infared
Visible
Ultraviolet
X-Ray
Gamma Ray

SHORTEST

Rabbits
Meet
In
Very
Unusual
Xciting
Gardens

Question 3

What is the correct order of visible light?

Answer 3

Red
Orange
Yellow
Green
Blue
Indigo
Violet

Question 5

What is the term luminous? Provide an example

Answer 5

produces its OWN light

and can convert other forms of light energy

examples - sun, forst, fireflies, computerscreen

Question 6

what is the term non-luminous?
Provide and example

Answer 6

DOES NOT produce it’s own light

examples - textbook, body, moon, e.t.c

Question 7

What is Bioluminescence?

Answer 7

Ability of a plant/animal to produce light

90% of all sea creatyres are bioluminescent

Question 8

Incadescent light

Answer 8

Produced by a material (ex.metals) at high temperature

increasing temperature causes filament to heat, release energy as light

VERY INEFFICENT
5% of electrical energy –> light
95% electrical energy –> heat

Question 9

Fluorscent Light

Answer 9

light emmited by some substances when exposed to electromagnetic radiation

CONTAINS PHOSPOR

CFLs (compact fluorescent light bulbs) are more efficient than incandescent bulbs, but still release up to 80% of their energy as heat -

ECO FRIENDLIER

Question 10

Phosphorescent Light

Answer 10

The ability to store the energy from a source of light and then emit it slowly over a long period.

(GLOW IN THE DARK STICKERS)

Question 11

chemiluminescence

Answer 11

light produced from a chemical reaction without a change in temperature
aka “cool light”
all forms of bioluminescence are special kinds of chemiluminescence

Ex. luminol
– detects blood
(reacts with iron)

GLOW STICKS, USED IN CRIME SCENES

Question 12

Triboluminescence

Answer 12

Materials that emit light when they are mechanically stimulated, such as rubbing, grinding, impact, stretching, and compression.

LIFESAVERS CANDY

Question 13

Electric discharge

Answer 13

Electric current passes through the air or another gas to produce light!

LIGHTNING , NEON SIGNS

Question 14

What are primary colours of light?

Answer 14

Red, Blue Green

Question 15

What are secondary colours of light?

Answer 15

Yellow, Cyan, Magenta

Question 16

RED + _________ = white light

Answer 16

red + CYAN = white light

Question 17

BLUE + _______ = white light

Answer 17

blue + YELLOW = white light

Question 18

GREEN + _______ = white light

Answer 18

green + MAGENTA = white light

Question 19

what is the umbra?

Answer 19

the part of the shadow in which all light rays from the light source are blocked.

SHARP SHADOW

Question 20

what is the penumbra?

Answer 20

The area of partial shadow from a non-point light source is called the penumbra.

FUZZY SHADOW

Question 21

what is the incident ray?

Answer 21

incident ray(i):
the incoming ray that strikes a surface

Question 22

what is the reflected ray(r)?

Answer 22

the ray that bounces off a reflective surface

Question 23

what is the Normal (N)?

Answer 23

the perpendicular line to a mirror surface (at right angles or 90 degrees from the reflected surface)

Question 24

what is the angle of angle of incidence(θi)?

Answer 24

angle of incidence(θi): the angle between the incident ray and the normal

Question 25

what is the angle of reflection(θr): the angle between the reflected ray and the normal

Answer 25

angle of reflection(θr): the angle between the reflected ray and the normal

Question 26

Incident ray

Answer 26

A ray which represents the incident (or incoming) light is an incident ray.

Question 27

reflected ray

Answer 27

A ray which represents the reflected(or outgoing) light is a reflected ray.

Question 28

Normal

Answer 28

A line perpendicular to the surface at the point of incidence is called a normal (N)

Question 29

Angle of Incidence

Answer 29

An angle between the incident ray and the normal is called an angle of incidence

Question 30

Angle of Reflection

Answer 30

An angle between the reflected ray and the normal is called an angle of reflection

Question 31

Diffuse Reflection

Answer 31

occurs when light rays reflect off a rough or uneven surface. They do not remain parallel but are scattered in different directions. The water surface is wavy and uneven. When the incoming light rays hit the rough surface, they do not reflect at the same angle and are no longer parallel.

Question 32

WHAT DOES SALT STAND FOR? * S *

Answer 32

Size – larger, smaller or same size as object

Question 33

WHAT DOES SALT STAND FOR? * A *

Answer 33

Attitude– upright, inverted, or laterally inverted

Question 34

WHAT DOES SALT STAND FOR? * L *

Answer 34

Location – infront or behind the mirror & distance from the mirror

Question 35

WHAT DOES SALT STAND FOR? * T *

Answer 35

Type – real or virtual

Question 36

What is refraction?

Answer 36

Refraction: the bending of light rays as they pass between two different media occurs due to changes in the speed of light in different mediums more that light slows down, the more the light is refracted

Question 37

What are two types of lenses?

Answer 37

Convex lens Concave Lens

Question 38

Convex Lens

Answer 38

converge light examples - microscope, manifying glass, camera *Lenses that are thickest in the middle; they cause parallel incident rays to converge through a single point after refraction

Question 39

Concave Lens

Answer 39

diverge light examples - flashlight, telescope, binoculars, *In a diverging lens, parallel light rays diverge after refraction from the lens *Diverging lenses are thinnest in the middle, and thickest at the edge

Question 40

what is a lens?

Answer 40

optical device made up of clear materials that send light in different ways