Exam Review: Phys

Question 1

What is refraction?

Answer 1

The bending or change in direction of light when it travels from one medium into another

Question 2

What is the angle of refraction?

Answer 2

The angle between the refracted ray and the normal

Question 3

What are the rules for refraction?

Answer 3

1. Incident Ray, refracted Ray, normal all line in same plane
2. Light bends towards the normal when the speed of light in a medium is slower
3. Light bends away from the medium when the speed of light in a medium is faster

Question 4

What is the index of refraction?

Answer 4

N= c/v

The ratio of the speed of light in a vacuum to the speed of light in a medium

Can also be written as:

N= sin <i></i>

Question 5

What does n mean in the equation n=c/v?

Answer 5

N= index of refraction

Question 6

What does c mean in the equation n=c/v?

Answer 6

C= Speed of light

Question 7

What does v mean in the equation n=c/v?

Answer 7

V= speed of light in a medium

Question 8

Do you add dimensions on the end of answers using n=c/v? Why or why not?

Answer 8

No.

N is dimensionless and c and v cancel eachother out

Question 9

What is the critical angle?

Answer 9

The angle of incidence that results in an angle of refraction of exactly 90 degrees

Question 10

What is total internal reflection?

Answer 10

Angle of incidence is greater than the critical angle & the ray is reflected back into the first medium

Question 11

Images in a diverging mirror…

Answer 11

• Always virtual
• Smaller
• Upright

Useful in stores for security mirrors

Question 12

How do you locate an image in a converging lens?

Answer 12

1. Parallel, through Focus
2. Straight through O
3. Through Focus, parallel

Draw lines from top of image
(SALT)

Question 13

What does SALT stand for?

Answer 13

Size
Attitude (upright/inverted)
Location
Type (virtual/real)

Question 14

Describe an image in a converging mirror if the object is AT the focus

Answer 14

No clear image is produced

Question 15

Describe an image in a converging mirror if the object is between the focus and the lens

Answer 15

The image is virtual

Question 16

What is a plane

Answer 16

Flat

Question 17

What is an incident Ray

Answer 17

An incoming Ray that strikes a surface

Question 18

What is a reflected Ray?

Answer 18

A Ray that bounces off a reflective surface

Question 19

What is the normal?

Answer 19

Perpendicular line to a mirror surface

Question 20

What is the angle of incidence?

Answer 20

Angle between incident Ray and the normal

Question 21

What is the angle of reflection?

Answer 21

Angle between reflected Ray and the normal

Question 22

What does the law of reflection state?

Answer 22

1. Angle of incidence = angle of reflection

2. Incident Ray, reflected rays and the normal are all in the same plane

Question 23

What is specular reflection?

Answer 23

The reflection of light off a smooth surface

Question 24

What is diffuse reflection?

Answer 24

The reflection of light on irregular/dull surfaces

Question 25

What is a virtual image?

Answer 25

An image formed by light coming from an apprentice light source and not actually arriving or coming from actual image location

Question 26

Describe images in plane mirrors

Answer 26

1. The distance from the object to the mirror is the same as from the image to the mirror 2. Object-image line = perpendicular to mirror

Question 27

Describe images in plane mirrors

Answer 27

Same size, upright, behind the mirror, virtual

Question 28

What's another word for a concave mirror?

Answer 28

Converging

Question 29

What's another word for a convex mirror?

Answer 29

Diverging

Question 30

What is the centre of curvature

Answer 30

The centre of the sphere whose surface has been used to make the mirror

Question 31

What is the principal axis?

Answer 31

The line through the centre of curvature to the midpoint of the mirror

Question 32

What is the vertex?

Answer 32

The point where the principal axis meets the mirror

Question 33

What does converge mean?

Answer 33

To meet at the same point

Question 34

What is the focus?

Answer 34

Where light rays parallel to the principal axis will be reflected off the mirror through a single point

Question 35

What are four ways to find an image in a concave mirror?

Answer 35

1. Parallel and through the focus 2. Through the focus and parallel 3. Through C and back along the same line 4. To V and reflected at an equal angle

Question 36

What is visible light?

Answer 36

Electromagnetic waves that the human eye can detect

Question 37

What is the electromagnetic spectrum?

Answer 37

The classification of electromagnetic waves by energy

Question 38

List the different wave types from lowest to highest energy

Answer 38

``` Radio waves Microwaves Infared Visible light Ultraviolet X-rays Gamma rays ```

Question 39

What can radio waves do?

Answer 39

Signals, wifi, cellphones

Question 40

What can microwaves do?

Answer 40

Microwave ovens, telecommunications

Question 41

What can infared light do?

Answer 41

Remotes, lasers, physical therapy

Question 42

What can visible light do?

Answer 42

Human vision, rainbows

Question 43

What can ultraviolet light do?

Answer 43

Skin tan/sunburn, skin cancer, kills bacteria, vitamin D

Question 44

What can X-rays do?

Answer 44

Medical imaging, cancer treatment, security scanning

Question 45

What can gamma rays do?

Answer 45

Cancer treatment, product of nuclear decay

Question 46

What do triangular prisms do in respect to the speed of light?

Answer 46

They slow down the speed of light slower than what it travels in the vacuum of space and so the colours split (rainbow)

Question 47

Define luminous

Answer 47

Produces its own light

Question 48

Define non-luminous

Answer 48

Does not produce its own light

Question 49

Explain incandescent lights

Answer 49

Light produced from high temperature

Question 50

Electric discharge?

Answer 50

Light produced by passing electric current though a gas (neon lights)

Question 51

Phosphorescence

Answer 51

Light produced by absorption of UV light that emits visible light over time

Question 52

Fluorescence

Answer 52

Immediate emission of visible light from absorption of UV light

Question 53

Why are fluorescent lights better than incandescent lights?

Answer 53

Less energy to operate, produce less heat = less heat loss

Question 54

What is bioluminescence

Answer 54

Light produced in living organisms by chemical reaction (little or no heat is produced)

Question 55

What is triboluminescence

Answer 55

Light produced from friction of certain crystals

Question 56

What are LED lights?

Answer 56

Light produced from electric current flowing in semi conductors

Question 57

What is a semi conductor?

Answer 57

Material that allows electric current to flow in only one direction

Question 58

What is an incident light?

Answer 58

Light emitted from a source that strikes an object

Question 59

Define transparent

Answer 59

Material transmits all or almost all incident light

Question 60

Define translucent

Answer 60

Material transmits some incident light but absorbs/reflects the rest

Question 61

Opaque

Answer 61

Material doesn't transmit any incident light

Question 62

Does the eye open wider or close up when it's darker?

Answer 62

Opens wider

Question 63

What can an eyelid be compared to?

Answer 63

Windshield wipers

Question 64

What causes people to be near or far sighted?

Answer 64

When the focus is off the retina (before or after)

Question 65

What is the iris?

Answer 65

A muscle that expands and contracts to let more/less light in through the pupil

Question 66

Lens _____ is changed so the amount of bending is changed

Answer 66

Thickness

Question 67

What is the lens' job?

Answer 67

To make the light rays hit the same point (hopefully the retina)

Question 68

Far sighted people...

Answer 68

Focus after the retina

Question 69

Near sighted people...

Answer 69

Focus before the retina