lenses and the eye

Question 1

how does a lens form an image

Answer 1

by refracting light

Question 2

what happens in a convex lens

Answer 2

parallel rays of light are brought to a focus at the principle focus

Question 3

what is a convex lend also known as

Answer 3

converging

Question 4

what is the focal length

Answer 4

the distance from the lens to the principle focus

Question 5

what is the focal length determined by

Answer 5

refractive index

curvature of the 2 surfaces of the lens

Question 6

what happens in a concave lens

Answer 6

parallel rays of light diverge as if coming form the principle focus

Question 7

what is another name for a concave lens

Answer 7

diverging

Question 8

what causes long sightedness

Answer 8

the eyeball being too short

the eye lens being unable to focus

Question 9

what causes short sightedness

Answer 9

the eyeball being too long

the eye lens being unable to focus

Question 10

what is the image distance of an object placed beyond 2F

Answer 10

between f and 2f on the other side

Question 11

what is the nature of the image of an object beyond 2f

Answer 11

real,inverted,smaller than the object

Question 12

what are the application examples of an object beyond 2f

Answer 12

film

digital comera

Question 13

what is the image position of an object at 2f

Answer 13

2f on the other side

Question 14

what is the nature of the image of an object at 2f

Answer 14

real, inverted, same size as object

Question 15

what is an application example of an object at 2f

Answer 15

inverter

Question 16

what is the image position of an object between f and 2f

Answer 16

beyond 2f on the other side

Question 17

what is the nature of the image of an object between f and 2f

Answer 17

real,inverted, larger than object

Question 18

what is an application example of an object between f and 2f

Answer 18

projector

Question 19

what is the image position of an object less than f

Answer 19

on the same side as the object

Question 20

what is the nature of the image formed less than f

Answer 20

virtual, upright, larger than the object

Question 21

what is an application example of an image less than f

Answer 21

magnifying glass

Question 22

what is the function of the retina

Answer 22

the light-sensitive cells around the inside of the eye

Question 23

what is the function of the lens

Answer 23

focuses light onto the retina

Question 24

what is the function of the cornea

Answer 24

transparent layer that protects the eye and helps to focus light onto the retina

Question 25

what is the function of the pupil

Answer 25

the central hole formed by the iris, light enters the eye throughout the pupil

Question 26

what is the function of the iris

Answer 26

coloured ring of muscle that controls the amount tot light entering the eye

Question 27

what is the function of the ciliary muscles

Answer 27

attached to the lens by suspensory ligaments | the muscles change the thickness of the eye

Question 28

what type of lens corrects long sightedness

Answer 28

converging

Question 29

what type of lens corrects short sightedness

Answer 29

diverging

Question 30

what type of lens is used in the eye

Answer 30

variable focus | converging lens

Question 31

what type of lens is used in the camera

Answer 31

fixed focus | converging lens

Question 32

how can adjust the focus in an eye

Answer 32

change the thickness of the lens

Question 33

how can you adjust the focus in a camera

Answer 33

adjust the lens position

Question 34

how is an image detected in the eye

Answer 34

light-sensitive cells on the retina

Question 35

how is an image detected in a camera

Answer 35

photographic film or CCD sensors

Question 36

how is the brightness controlled in the eye

Answer 36

iris controls width of pupil

Question 37

how is the brightness controlled in a camera

Answer 37

adjustment of aperture "stop"

Question 38

what is the nature of an image in the eye

Answer 38

real,inverted,smaller than object

Question 39

what is the nature of an image in a camera

Answer 39

real,inverted,smaller than object