optics test - 4/22/24

Question 1

what is incandescence?

Answer 1

occurs when objects that are heated to high temperatures emit light. colours change with temp. examples include burning candles.

Question 2

what type of light emission is produced when electric currents pass through gasses, causing them to glow?

Answer 2

electric discharge; examples include lightning and neon signs

Question 3

what is fluorescence?

Answer 3

when objects emit light immediately after absorbing ultraviolet light. examples include laundry detergents, highlighter pens, etc…

Question 4

what is phosphorescence?

Answer 4

when materials absorb ultraviolet (UV) light and emit it over time (ex: glow in the dark objects)

Question 5

what is chemiluminescence?

Answer 5

Light produced as a result of a chemical reaction without producing heat. (ex: light sticks + glow sticks)

Question 6

what is bioluminescence?

Answer 6

Chemiluminescence in living organisms (ex: certain bacteria, glow worms, fish)

Question 7

what is triboluminescence?

Answer 7

light produced from friction with crystals, first observed by francis bacon

Question 8

what is light-emitting diodes (LEDs)?

Answer 8

electronic devices that emit light when electric currents pass through them, more energy efficient than incadescent bulbs, used in things like traffic lights and christmas lights

Question 9

what is the cornea?

Answer 9

clear tissue that refracts light; makes it go into eye

Question 10

what is the lens?

Answer 10

focuses the image that cornea creates by fine tuning it

Question 11

what are the ciliary muscles?

Answer 11

muscles that assist in the process of focusing the image (lens’ job) – they change the shape of the lens

Question 12

what is the pupil?

Answer 12

entrance that allows light enter the eye

Question 13

what is the iris?

Answer 13

controls size of pupil (coloured part of eye)

Question 14

what is the retina?

Answer 14

screen that images are projected into; located in abck of eye

Question 15

what is the optic nerve?

Answer 15

sends messages to the brain about what is seen by being the receptors in the retina

Question 16

what causes vision problems?

Answer 16

refraction

Question 17

what is myopia?

Answer 17

nearsightedness, caused by more refraction from distant objects, causes focusing of images of nearby objects in front of the retina; causing blur

how to treat: convex lenses

Question 18

what is hyperopia?

Answer 18

farsightedness, caused by vertically stretched eye shape, focuses images of nearby objects BEHIND retina

Question 19

types of eye surgeries

Answer 19

LASIK, PRK
procedure:
1. Measurement of cornea’s shape and thickness.
2. Cutting a thin flap of the cornea.
3. Reshaping the cornea with laser.
4. Repositioning the corneal flap.

Question 20

SALT with plane mirrors?

Answer 20

S - Same size
A - Upright
L - Same distance, behind mirror
T - Virtual

Question 21

SALT with concave mirrors – beyond 2F?

Answer 21

S - Smaller
A - Inverted
L - Right underneath object
T - Real

Question 22

SALT with concave mirrors – between 2F and F?

Answer 22

S - Larger
A - Upside down (inverted)
L - Further away from mirror
T - Real

Question 23

SALT with concave mirrors – directly on F?

Answer 23

no image formed

Question 24

SALT with concave mirrors – less than F? (closest to mirror)

Answer 24

S - Larger
A - Right side up
L - In front of mirror
T - Virtual

Question 25

SALT with converging lens?

Answer 25

S - smaller A - inverted L - between 2F and F T - real

Question 26

applications of lenses: the camera

Answer 26

**Cameras capture light from distant objects, forming smaller, real images on film or digital sensors.** A converging lens produces an inverted, real image when the object is beyond twice the focal length.

Question 27

applications of lenses: the movie projector

Answer 27

Projects large, inverted, real images on a screen. Film must be between the focal length and twice the focal length.

Question 28

applications of lenses: the magnifying glass

Answer 28

Simple converging lens (convex) with object between focal point and lens. Produces enlarged, virtual image on same side as object.

Question 29

applications of lenses: the compound microscope

Answer 29

Two converging lenses create two images: one real and one virtual. Real image formed by objective lens, virtual image seen through eyepiece lens.

Question 30

what is mirage?

Answer 30

optical illusion caused by the bending of light rays due to temperature variations in the air; creating the illusion of water or objects that aren't actually there

Question 31

what is inferior mirage?

Answer 31

Inferior mirage: hot ground, bends light, objects seem lower, illusionary water.

Question 32

what is superior mirage?

Answer 32

Superior mirage: cool ground, bends light, objects seem higher, illusionary elevation.