Eyes

Question 1

Iris

Answer 1

Controls how much light enters pupil

Question 2

Pupil

Answer 2

Allows light to pass through as it enters the eye

Question 3

Lens

Answer 3

Refracts light to focus it on to the retina

The amount of refraction an be altered by changing the thickness and curvature of the lens

Question 4

Ciliary muscles

Answer 4

Adjust to make the shape of the lens more or less curved so light can be focuses at varying distances

Question 5

Suspensory ligaments

Answer 5

Slacken or stretch as the ciliary muscles contract or relax to adjust the thickness and curvature of the lens

Question 6

Retina

Answer 6

Contains light receptors which cause electrical impulses to be sent to the brain when light is detected

Question 7

What causes and corrects long sight?

Answer 7

Too short eyeball
Inability to focus

Converging lens

Question 8

What is short sight and what treats it?

Answer 8

Caused by too long an eyeball or inability to focus

Corrected by a diverging lens

Question 9

Cornea?

Answer 9

Focuses light as it enters the eye

Question 10

What is the function of the ciliary muscles?

Answer 10

To change the shape of the lens

Question 11

What is the function of the lens?

Answer 11

To focus the light from the object into the retina

Question 12

What should the variables be if you want to draw a line graph?

Answer 12

Continuous

Question 13

What does repeating tests a number of times and taking an average do?

Answer 13

Improves the reliability

Question 14

What does the aqueous humour do?

Answer 14

Supports front of the eye

Question 15

What is the aqueous humour?

Answer 15

Transparent watery liquid

Question 16

What is the iris?

Answer 16

Coloured ring of muscle that controls amount of light entering eye

Question 17

What is the retina?

Answer 17

The light sensitive cells around the eye

Question 18

How are the ciliary muscles attached to the lens?

Answer 18

By suspensory ligaments

Question 19

What do eye muscles do?2

Answer 19

Move the eye

In the socket

Question 20

Why do we have a blind spot?

Answer 20

Because this is a region where no light sensitive cells are present (and so is not sensitive to light)

Question 21

What is the vitreous humour?

Answer 21

Transparent jelly like substance that supports the back of the eye

Question 22

What does the aqueous humour do?

Answer 22

Supports front of the eye

Question 23

What is the aqueous humour?

Answer 23

Transparent watery liquid

Question 24

What is the iris?

Answer 24

Coloured ring of muscle that controls amount of light entering eye

Question 25

What is the retina?

Answer 25

The light sensitive cells around the eye

Question 26

How are the ciliary muscles attached to the lens?

Answer 26

By suspensory ligaments

Question 27

What do eye muscles do?2

Answer 27

Move the eye | In the socket

Question 28

Why do we have a blind spot?

Answer 28

Because this is a region where no light sensitive cells are present (and so is not sensitive to light)

Question 29

What is the vitreous humour?

Answer 29

Transparent jelly like substance that supports the back of the eye

Question 30

What is the unit of lens power?

Answer 30

D | dioptre

Question 31

What causes long sight?

Answer 31

Eyeball being too short | Eye lens being unable to focus

Question 32

What causes short sight?

Answer 32

Eyeball being too long | Eye lens being unable to focus

Question 33

How is an eye similar to a camera?

Answer 33

The CCDs in a digital camera is equivalent to the retina of an eye

Question 34

Why is it advantageous to have a flatter lens?

Answer 34

The lens can be manufactured thinner

Question 35

For a given focal length, how does refractive index change the thickness of the lens?

Answer 35

The greater the refractive index the flatter the lens

Question 36

What type of lens does the eye have?

Answer 36

Variable focus converging lens

Question 37

What type of lens does the camera have?

Answer 37

Fixed converging lens

Question 38

How does the eye adjust the focus?

Answer 38

Ciliary muscles alter the lens thickness

Question 39

How does a camera adjust the focus?

Answer 39

Adjustment of lens position

Question 40

What image does an eye form?

Answer 40

Real Inverted Magnification less than 1

Question 41

How does the eye detect an image?

Answer 41

Light sensitive cells in the retina

Question 42

How does the camera detect an image?

Answer 42

Photographic film | Or CCD sensors in a digital camera

Question 43

How does the eye control brightness?

Answer 43

The iris controls the width of the pupil

Question 44

How does the camera control the brightness?

Answer 44

Adjustment of aperture 'stop'

Question 45

How does a converging lens correct long sight?

Answer 45

Makes the Rays diverge less The eye lens can then focus Ray's on to the retina Adds to the focusing power of the eye lens

Question 46

How can short sight be corrected by a diverging lens?

Answer 46

Counteracts some of the excess focusing power of the eye lens

Question 47

Explain short sight?

Answer 47

Image formed in front of the retina The eyeball is too long Eye lens is too powerful The eye muscle can't make the eye lens thick enough to focus the image of a far away object in the retina

Question 48

Explain long sight?

Answer 48

Image is formed behind the retina | The lens can't be made thick enough to focus the image on the retina

Question 49

How can you manufacture a flatter and thinner lens?

Answer 49

Using a material with a higher refractive index | Because the lens surface would be less curved

Question 50

Why use a material with a high refractive index?

Answer 50

The lens can be flatter and thinner | Lens surface is less curved

Question 51

How do you see something far away?

Answer 51

Eye lens becomes thinner (via the ciliary muscles) to keep in focus The fibres in the ciliary muscles are parallel to the circular edge of the eye lens

Question 52

How do you see something close

Answer 52

The fibres in the ciliary muscles are parallel to the circular edge of the eye lens When they contract they shorten and squeeze the eye lens making it thicker

Question 53

Where in the eye does might enter?

Answer 53

The pupil