The Eye and The Camera

Which part of the eye controls how much light enters the eye?

• The iris

• The pupil

• The lens

• The retina

Answer explanation

The light enters through the pupil but the iris controls the size of the pupil, and thus how much light enters.

Letter _ is identifying the lens.

Answer explanation

The light enters through the pupil but the iris controls the size of the pupil, and thus how much light enters.

Some of the features of a camera and an eye have similar functions. Which part of the eye does the same job as Z on the camera?

• The retina

• Lens

• Iris

• Optic nerve

Answer explanation

Z is the film or CCD and detects the light; in the eye, the retina does this job.

What kind of signal is sent down the optic nerve?

• Radio

• Heat

• Electromagnetic

• Electrical

Answer explanation

An electrical signal is sent down the optic nerve where the brain processes it so the image we see is not inverted.

Which statement(s) is/are true about the images made by a camera but are not true about the images made by the eye?

• The image is real.

• The image is virtual.

• The image can be saved.

• The image is inverted.

• The image is not inverted.

Answer explanation

Both the images in the eye and the camera are inverted.

In the camera, the images are real and can be saved.

In the eye, the images are virtual and cannot be saved.

True or False: There is a blind spot on the retina.

• True

• False

Answer explanation

There is a blind spot where the optic nerve connects to the retina.

What is the name of the protective layer of the eye?

• The cornea

• The sclera

• Vitreous humor

• Glaucoma

Answer explanation

The sclera is the protective layer.

The cornea is the transparent layer over the iris, lens and pupil.

The vitreous humour is the fluid inside the eye.

Glaucoma is a condition that affects the eye.

What happens to the light as it goes through the cornea?

• It reflects

• It absorbs

• It refracts

• It scatters

Answer explanation

As light enters the cornea, it refracts and is bent towards the retina.

The ciliary muscles change the shape of the lens to allow for focus on both near and far objects. How does this happen in a camera?

• The angle of the lens changes.

• The aperture gets wider and narrower.

• The lens gets thicker and thinner.

• The lens moves backwards and forwards.

Answer explanation

The focusing screw controls the movement of the lens backwards and forwards.

True or False: different colour irises allow different amounts of light into the eye.

• True

• False

Answer explanation

Iris colour is due to genetics and has no control over the amount of light let in. The iris controls the size of the pupil and therefore how much light enters.