Light and our Eyes

Question 1

What are luminous objects?

Answer 1

Objects that produce light.

Question 1

What form is light?

Answer 1

A wave.

Question 2

Give an example of a luminous object.

Answer 2

The Sun

Question 3

What are non-luminous objects?

Answer 3

Objects that don’t produce light.

Question 4

Give an example of a non-luminous object.

Answer 4

A book

Question 5

What do light waves transfer?

Answer 5

Energy

Question 6

What does light travel fastest through and why?

Answer 6

Light travels fastest through a vacuum because there are no particle obstructing it.

Question 7

What is reflection?

Answer 7

Reflection of light is when a light ray bounces off a surface and changes direction, continuing to travel in a straight line but in a different direction.

Question 8

What is the difference between specular reflection and diffuse reflection?

Answer 8

Specular reflection is when light rays reflect off a smooth, shiny surface, so there is a clear reflection. Diffuse reflection is when light rays are reflected off a rough surface, and the light rays are scattered.

Question 9

Angle of ______ = angle of _______

Answer 9

incidence and reflection

Question 10

What is the normal?

Answer 10

A line at a right angle to the surface.

Question 11

How are the angles of incidence and reflection measured?

Answer 11

Between the incident light ray / reflected light ray and the normal.

Question 12

What is refraction?

Answer 12

Refraction happens when light rays move through a more or less dense substance.

Question 13

Will light travel through transparent and opaque materials?

Answer 13

Yes to transparent but not to opaque.

Question 14

What does opaque mean?

Answer 14

Not see-through.

Question 15

What is a medium?

Answer 15

Any substance that light travels through.

Question 16

What happens when light goes from a more dense medium to a less dense medium?

Answer 16

The light bends away from the normal.

Question 17

What happens when light goes from a less dense medium to a more dense medium?

Answer 17

The light bends towards the normal.

Question 18

How do we see?

Answer 18

When a luminous object produces light, it reflects off other non-luminous objects, and some of that reflected light goes into our eyes.

Question 19

What does a lens do?

Answer 19

A lens refracts light.

Question 20

What is the different between convex and concave lenses?

Answer 20

Convex lenses bulge outwards, and cause rays of light to converge to a focus, whereas concave lenses scatter light rays.

Question 21

What is the cornea?

Answer 21

A transparent window with a convex shape in our eyes.

Question 22

Why does the convex lens behind the cornea change shape?

Answer 22

To focus light from objects at varying distances.

Question 23

What is the iris?

Answer 23

The coloured part of our eye, controls the amount of light entering the eye.

Question 24

What does the retina do?

Answer 24

Forms images. Retina cells are photosensitive (sensitive to light).

Question 25

What is an absorber?

Answer 25

Something that absorbs the energy carried by light waves.