Vision

Question 1

What is the sclera?

Answer 1

Thick white outer covering of the eyeball that’s attached to 6 muscles

Question 2

What’s the cornea?

Answer 2

Front part of sclera, covers up iris and pupil. It’s coloured and transparent

Question 3

What’s iris

Answer 3

Colours r brown, blue, green, and grey. Ring of muscle that contracts and relaxes automatically to regulate amount of light entering eye.

Question 4

What r ciliary muscles?

Answer 4

Hold lens in place, attached to lens by ligaments

Question 5

What’s retina

Answer 5

Layer of light sensitive cells at back of eye and has many blood vessels and nerves

Question 6

What r rods

Answer 6

Are 120 million in 1 eye. Colours r black, white, and shades of grey. Sensitive to levels of light (detect dim light)

Question 7

What r cones

Answer 7

Are 6 million in 1 eye. Sensitive to colour (detects bright light)

Question 8

What is optic nerve

Answer 8

Sends nerve signals to brain

Question 9

What’s blind spot

Answer 9

Area of retina where optic nerve and blood vessels connect. No rods or corns

Question 10

What’s normal vision?

Answer 10

6/6 meters, or How clear or sharp vision normally is at 6 meters. In NV, cornea and lens reflect light to produce clear image in retina. Image is upside down and reversed

Question 11

What r refractive vision problems?

Answer 11

When eye can’t properly focus on image in retina

Question 12

What’s myopia

Answer 12

Nearsightedness. Can c nearby things clearly but not distant objects. 1/3 of population has it. Focal point of an eye with myopia is in front of retina.

Question 13

What’s hyperopia

Answer 13

Farsightedness. Eye can c distant objects clearly but has trouble focusing on close-up objects. 1/4 of population. Focal point of eye with this is behind the retina

Question 14

How does lens change when u focus on distant object?

Answer 14

Light doesn’t bend much, ciliary muscles relax and lens is normal shape

Question 15

How does lens change when u focus on nearby object

Answer 15

Light rays enter at angle, refract and change direction and ciliary muscles contract

Question 16

How does astigmatism affect eye?

Answer 16

Cornea has irregular curvature, so visions blurred

Question 17

How does presbyopia affect eye

Answer 17

Eye can’t focus on nearby or faraway objects due to age

Question 18

How do u correct myopia?

Answer 18

Concave lens in front of eye spreads incoming light

Question 19

How do u correct hyperopia?

Answer 19

Convex lens used to slightly refract light before it enters eye

Question 20

What happens during laser surgery?

Answer 20

Fine bean of light’s used to reshape the cornea to adjust focal point

Question 21

Define refract

Answer 21

To make a ray of light Change direction when it enters at angle

Question 22

What’s light

Answer 22

Form of energy that can be detected by human eye. It travels from source directly to your eyes, some bounce off objects and travels to eye

Question 23

Explain sources of light

Answer 23

Light energy comes from natural and artificial sources. Sun’s most important natural source of light.

Question 24

What’s luminous

Answer 24

Objects that emit (give off) energy in form of light (sun, candle). In luminous objects, input energy transforms into light energy. Things that r very hot become luminous at height temperature and begin to emit light

Question 25

What’s nonluminous

Answer 25

Doesn’t emit light, only reflects light from other sources (moon, books, etc)

Question 26

What’s incandescence

Answer 26

Process of emitting light energy because of high temperature. These light sources have Large amounts of input energy because of thermal energy, therefore these light sources aren’t efficient

Question 27

What’s thermal energy

Answer 27

Thermal energy can heat metal to high temperature, and emits light (from dull red to yellow to white to blue-white as object gets hotter and hotter)

Question 28

What’s phosphorescence

Answer 28

Process of emitting light from short time after receiving energy from another source, (e.g. Light switches that glow in the dark)

Question 29

What’s electric discharge

Answer 29

Process of emitting light because of electricity passing through a gas (lightning)

Question 30

What’s fluorescence

Answer 30

Process of emitting light while receiving energy from another source (fluorescence tubes used in schools). Fluorescence tubes use electric discharge and phosphorescence

Question 31

What’s chemiluminescence

Answer 31

Process of changing chemical energy into light energy with little or no change in temperature (glow sticks)

Question 32

What’s bioluminescence

Answer 32

Some living things can make themselves luminous using a chemical reaction similar to chemiluminescence (fire flies, fish)

Question 33

What’s shadow

Answer 33

An area where light has been blocked by a solid object

Question 34

What’s umbra

Answer 34

Dark part of shadow, some light from the source reaches here

Question 35

What’s penumbra

Answer 35

Lighter part of shadow, some light from source comes here

Question 36

What’s transparency

Answer 36

Measure of how much light can pass through a material

Question 37

What’s transparent material

Answer 37

Particles let light pass through readily (plastic wrap)

Question 38

What’s translucent material

Answer 38

Particles transmit light but also reflect some so a clear image can’t be seen through material (frosted glass, candle)

Question 39

What’s opaque material

Answer 39

Particles don’t allow any light to pass through. All light energy is reflected or absorbed (stone, brick)

Question 40

Describe absorbing and reflecting light

Answer 40

Light strikes an opaque material, no light’s transmitted. Some of the light energy is absorbed by material and is converted into thermal energy, and some rays of light bounce off the object to be reflected

Question 41

What describes the amount of light energy that’s absorbed it reflected?

Answer 41

Colour/sheen (shininess). Black and dark coloured materials absorb more light energy than white and light coloured materials

Question 42

What’s a visible spectrum?

Answer 42

Bond of colour u can c in a rainbow. 6 main colours r red, orange, yellow, green, blue, and violet- called spectral colours

Question 43

What’s white light

Answer 43

Spectral colours, red to violet. Different spectral colours are reflected and absorbed depending on characteristics of the object. This is why we c object in specific colours (if blue lights reflected off object, we c blue). If all parts of visible spectrum r reflected, we c the objects as white. If none’s reflected, we c black

Question 44

What’s electromagnetic spectrum

Answer 44

Entire range of radiant energies other than light r (UV) ultraviolet radiation, x-ray, and microwaves

Question 45

What’s wave

Answer 45

Vibration that transfers energy from 1 location to another. The vibration’s a regular repeated motion that produces regular wave patterns. Wave can be created by stretching out length of rope (or springs) and vibrating 1 end back and forth. Light behaves in a way similar to mechanic waves. Reflects off surfaces or changes directions when passing through different materials

Question 46

What’s wavelength

Answer 46

Distance between 2 adjacent crests or 2 adjacent troughs

Question 47

What’s crest

Answer 47

Farthest point above resting position

Question 48

What’s trough

Answer 48

Farthest point below resting position

Question 49

What’s amplitude

Answer 49

Maximum distance above or below resting position

Question 50

What’s frequency

Answer 50

Vibration of number of cycles In a period of time. It’s indicated in hertz (h2) or cycles per sec. for waves, a cycle’s a complete wavelength. Energy of different parts of the electromagnetic spectrum depend on wavelength, and high frequencyC has high energy