8K Light

Question 1

What does luminous mean?

Answer 1

Creates light

Question 2

What is a material that blocks all light called?

Answer 2

opaque

Question 3

What is the difference between a transparent and a transluscent material?

Answer 3

Transparent materials let light pass straight through whereas transluscent materials only allow some of the light to pass through and usually not in a straight line.

Question 4

What does it mean if a material transmits light?

Answer 4

It means the light passes through

Question 5

What does it mean if a material scatters light?

Answer 5

It means the light ends up going in all different directions

Question 6

WHen a material absorbs light (ie. black objects) what happens to the energy from the light?

Answer 6

The light energy is transferred to thermal energy

Question 7

What is the cornea for?

Answer 7

It is transparent, it protects the eye and helps focus the light

Question 8

Put the following part of the eye in order for seeing an object

Answer 8

retina, cornea, lens, pupil, optic nerve

Question 9

What is the lens for?

Answer 9

To focus the incoming light on the retina

Question 10

How does the eye change the shape of the lens?

Answer 10

It has muscles that pull the lens

Question 11

What is the pupil?

Answer 11

The hole in the eye

Question 12

Why does the pupil get larger and smaller

Answer 12

The pupil allows the right amount of light into the eye depending on how bright it is

Question 13

What is the purpose of the retina?

Answer 13

To detect light and pass a signal to the optic nerve

Question 14

What is the purpose of the optic nerve?

Answer 14

To send impulses to the brain carrying the information about what light is hitting the retina

Question 15

What is a plane mirror?

Answer 15

A flat reflective surface

Question 16

What is the incident ray?

Answer 16

Ray of light shining IN towards the mirror or glass block

Question 17

What is the reflected ray?

Answer 17

The light ray after it has been reflected

Question 18

What is the normal?

Answer 18

A dotted line draw at right angles to the mirror

Question 19

Which diagram has the angle of incidence, i, and the angle of reflection, r, labelled correctly?

Answer 19

A

Question 20

What is the rule of reflection?

Answer 20

angle of incidence = angle of reflection

Question 21

How does light travel along a periscope?

Answer 21

Light is reflected off 2 mirrors, each at 45 degrees

Question 22

Describe the image seen in a mirror?

Answer 22

The image in a mirror is the same size as the object, the same distance behind the mirror but is flipped from lift to right.

Question 23

What is refraction?

Answer 23

When light enters a new medium and changes direction

Question 24

Where does refraction take place?

Answer 24

At the interface between 2 materials

Question 25

Why does refraction take place?

Answer 25

Because the light speed up or slows down

Question 26

Which way does light bend when it slows down?

Answer 26

Slows down = bends towards the normal

Question 27

Which way does light bend when it speeds up?

Answer 27

Speed up = away from the normal

Question 28

What is a lens?

Answer 28

A piece of specially shaped glass or plastic the either makes light rays come together or makes light rays separate

Question 29

Name 3 pieces of equipment that use lenses

Answer 29

microscope, telescope, glasses, contact lenses, cameras, eyes

Question 30

How can white light be split into the spectrum of colours?

Answer 30

Shine it through a triangular prism

Question 31

What is splitting of colour into a spectrum called?

Answer 31

dispersion

Question 32

Give the colours of the light spectrum in order

Answer 32

red, orange, yellow, green, blue, indigo, violet

Question 33

Why does a red object look red?

Answer 33

Red objects absorb all of the colours of light other than red. The red light is reflected into our eyes.

Question 34

Why does a blue object look blue?

Answer 34

Blue objects absorb all of the colours of light other than blue. The blue light is reflected into our eyes.

Question 35

Why does a black object look black?

Answer 35

Black object absorb all of the colours of light. Our brains process that as black.

Question 36

Why does a white object look white?

Answer 36

White objects reflect all of the colours of light. Our brains process a mixture of all the colours as white.