Unit 4.4

Question 1

Concave lens

Answer 1

A lens that curves inwards

Question 2

Convex lens

Answer 2

A lens that bulges outwards

Question 3

Cornea

Answer 3

A transparent covering over the iris of the eye; it bends light into the lens

Question 4

Focal length

Answer 4

The distance from a lens to its focus

Question 5

Lens

Answer 5

In the eye it is a flexible structure that enables light to be focused on the retina

Question 6

Long-sightedness (hyperopia)

Answer 6

The inability to focus on close objects because the eyeball is too long

Question 7

Optic nerve

Answer 7

A nerve that carries an electrical signal from the retina to the brain

Question 8

Real image

Answer 8

An image formed when rays of light do actually meet

Question 9

Retina

Answer 9

Nerve tissue at the back of the eye, consisting of cone cells and rod cells; light is converted into an electrical signal here

Question 10

Short-sightedness (myopia)

Answer 10

The inability to focus on distant objects because the eyeball is too short

Question 11

Accommodation

Answer 11

The ability of the lens of the eye to change its shape to adjust its focus