Light

Question 1

What is light?

Answer 1

A form of energy

Question 2

What type of waves are light waves?

Answer 2

Transverse waves

Question 3

True or false: light travels in straight lines

Answer 3

True

Question 4

At what speed does light travel?

Answer 4

300,000,000 m/s

Question 5

What is a luminous object?

Answer 5

An object that emits light.

Question 6

How do we see luminous objects?

Answer 6

The light from these objects enters the eyes.

Question 7

What is a non-luminous object?

Answer 7

An object that does not emit light.

Question 8

How do we see non-luminous objects?

Answer 8

Non-luminous objects reflect the light from luminous objects into the eyes.

Question 9

Define transparent:

Answer 9

allows light to pass through

Question 10

What is it called when an object allows some light to pass through?

Answer 10

Translucent

Question 11

Define opaque:

Answer 11

Allows no light to pass through

Question 12

What are the 4 rules for drawing ray diagrams?

Answer 12

The lines must be: straight, touch the objects, have arrows showing the direction of travel and reflected rays must join up with each other.

Question 13

Define specular reflection:

Answer 13

when each light ray is reflected at the same angle. The AoI = AoR

Question 14

Define diffuse reflection:

Answer 14

The reflected rays come back at different angles and in different directions.

Question 15

Is a mirror an example of specular or diffuse reflection?

Answer 15

Specular

Question 16

Is paper an example of specular or diffuse reflection?

Answer 16

Diffuse.

Question 17

Follow this link and correctly label the ray diagram: https://qph.fs.quoracdn.net/main-qimg-d46c2b33dfc74b08ec8536db6d17cc9b

Answer 17

A= Incident Ray. A’= Reflected Ray. N= Normal. P= angle of incidence. Q= angle of reflection

Question 18

What is the Incident Ray?

Answer 18

The light ray that comes from the light source and hits the object.

Question 19

What is the Reflected Ray?

Answer 19

The light ray that bounces off of a surface and into the eyes

Question 20

What is the Normal Line?

Answer 20

A line at 90 degrees, perpendicular to the mirror

Question 21

How are periscopes made?

Answer 21

By positioning two mirrors at 45 degrees to each other in a tube.

Question 22

What happens when light moves from a more or less dense transparent medium?

Answer 22

Refraction

Question 23

True or false: light bends as it moves from a more or less dense medium

Answer 23

True

Question 24

True or false: light waves do not change speed when they move from one medium to another

Answer 24

False

Question 25

If light goes from a LESS dense medium --> MORE dense medium, will it bend towards or away from the normal?

Answer 25

towards

Question 26

If light goes from a MORE dense medium --> LESS dense medium, will it bend towards or away from the normal?

Answer 26

Away

Question 27

Give an example of dispersion:

Answer 27

white light entering a water droplet/prism is refracted into a separate spectrum of light waves

Question 28

True or false: different colours refract more or less when passing through prisms and droplets.

Answer 28

true

Question 29

Which colour is refracted the most?

Answer 29

Violet

Question 30

Which colour is refracted the least?

Answer 30

Red

Question 31

Objects that look white ____ all colours of the spectrum.

Answer 31

Reflect

Question 32

Objects that look black ____ all colours of the spectrum.

Answer 32

Absorb

Question 33

Explain why a red bottle would look red.

Answer 33

A red object only reflects red light and absorbs all other colours.

Question 34

What happens when white light passes through a filter?

Answer 34

Only the colour of the filter can pass through and all other colours are absorbed.

Question 35

What are the colours in a light spectrum?

Answer 35

``` Richard - Red Of - Orange York - Yellow Gave - Green Battle - Blue In - Indigo Velvet - Violet ```

Question 36

Do pinhole cameras have a lens?

Answer 36

No

Question 37

What do pinhole cameras have instead of a lens?

Answer 37

A tiny hole.

Question 38

How many light rays from each point of the object enters a pinhole camera?

Answer 38

1

Question 39

How do pinhole cameras work?

Answer 39

1 light ray from each point on the objects enters the camera (travelling in a straight line), and inside they cross over, so the image is seen upside down.

Question 40

Label the this diagram : https://i.pinimg.com/236x/4b/39/25/4b39250884cd07e52eabdd94ce95f4cc--physics-revision-th-grade-science.jpg

Answer 40

``` 1 - Cornea 2 - Pupil 3 - Iris 4 - Lens 5 - Retina 6 - Ciliary Muscle 7 - Optic Nerve ```

Question 41

What is the function of the iris?

Answer 41

The coloured part of the eye and controls the amount of light which enters the eye.

Question 42

What is the function of the cornea?

Answer 42

A transparent layer at the front of the eye and focuses much of the light entering the eye.

Question 43

Are the cornea and lens convex or concave?

Answer 43

Convex

Question 44

What is the function of the ciliary muscle?

Answer 44

Changes the lens shape for focusing.

Question 45

What is the function of the pupil?

Answer 45

The hole where the light enters the eye.

Question 46

What is the name of the photo-sensitive cells at the back of the eye?

Answer 46

Retina

Question 47

What is the nerve that runs from the eye to the brain?

Answer 47

The optic nerve.

Question 48

How is the eye similar to the pinhole camera?

Answer 48

The light crosses over inside so the image is formed inverted.

Question 49

What is an absorber?

Answer 49

Anything that absorbs light.