topic 2

Question 1

cornea

Answer 1

refracts light into the eye

Question 2

iris

Answer 2

controls how much light enters the eye

Question 3

lens

Answer 3

refracts light, focusing it onto the retina

Question 4

retina

Answer 4

light sensitive, covered in receptor cells called rods and cones

Question 5

rods

Answer 5

sensitive in dim light, can’t sense colour

Question 6

cones

Answer 6

sensitive to colours, not good in dim light

Question 7

how does the eye look at distant objects

Answer 7

ciliary muscle relaxes, allowing suspensory ligaments to pull tight. this pulls the lens into a less rounded shape so light is refracted less.

Question 8

how does the eye look at near objects

Answer 8

ciliary muscles contracts, which slackens the suspensory ligaments. this makes the lens more rounded so light is refracted more.

Question 9

long sighted

Answer 9

unable to focus on near objects, occurs when eyeball is too short

Question 10

short sighted

Answer 10

unable to focus on distant objects, occurs when eyeball is too long

Question 11

which lens is suitable for long-sightedness

Answer 11

convex

Question 12

which lens is suitable for short-sightedness

Answer 12

concave