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Flashcards in Exam Review: Phys Deck (69):
1

What is refraction?

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

2

What is the angle of refraction?

The angle between the refracted ray and the normal

3

What are the rules for refraction?

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

4

What is the index of refraction?

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

5

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

N= index of refraction

6

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

C= Speed of light

7

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

V= speed of light in a medium

8

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

No.

N is dimensionless and c and v cancel eachother out

9

What is the critical angle?

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

10

What is total internal reflection?

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

11

Images in a diverging mirror...

-Always virtual
-Smaller
-Upright

Useful in stores for security mirrors

12

How do you locate an image in a converging lens?

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

Draw lines from top of image
(SALT)

13

What does SALT stand for?

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

14

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

No clear image is produced

15

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

The image is virtual

16

What is a plane

Flat

17

What is an incident Ray

An incoming Ray that strikes a surface

18

What is a reflected Ray?

A Ray that bounces off a reflective surface

19

What is the normal?

Perpendicular line to a mirror surface

20

What is the angle of incidence?

Angle between incident Ray and the normal

21

What is the angle of reflection?

Angle between reflected Ray and the normal

22

What does the law of reflection state?

1. Angle of incidence = angle of reflection
2. Incident Ray, reflected rays and the normal are all in the same plane

23

What is specular reflection?

The reflection of light off a smooth surface

24

What is diffuse reflection?

The reflection of light on irregular/dull surfaces

25

What is a virtual image?

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

26

Describe images in plane mirrors

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

27

Describe images in plane mirrors

Same size, upright, behind the mirror, virtual

28

What's another word for a concave mirror?

Converging

29

What's another word for a convex mirror?

Diverging

30

What is the centre of curvature

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

31

What is the principal axis?

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

32

What is the vertex?

The point where the principal axis meets the mirror

33

What does converge mean?

To meet at the same point

34

What is the focus?

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

35

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

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

36

What is visible light?

Electromagnetic waves that the human eye can detect

37

What is the electromagnetic spectrum?

The classification of electromagnetic waves by energy

38

List the different wave types from lowest to highest energy

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

39

What can radio waves do?

Signals, wifi, cellphones

40

What can microwaves do?

Microwave ovens, telecommunications

41

What can infared light do?

Remotes, lasers, physical therapy

42

What can visible light do?

Human vision, rainbows

43

What can ultraviolet light do?

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

44

What can X-rays do?

Medical imaging, cancer treatment, security scanning

45

What can gamma rays do?

Cancer treatment, product of nuclear decay

46

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

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

47

Define luminous

Produces its own light

48

Define non-luminous

Does not produce its own light

49

Explain incandescent lights

Light produced from high temperature

50

Electric discharge?

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

51

Phosphorescence

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

52

Fluorescence

Immediate emission of visible light from absorption of UV light

53

Why are fluorescent lights better than incandescent lights?

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

54

What is bioluminescence

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

55

What is triboluminescence

Light produced from friction of certain crystals

56

What are LED lights?

Light produced from electric current flowing in semi conductors

57

What is a semi conductor?

Material that allows electric current to flow in only one direction

58

What is an incident light?

Light emitted from a source that strikes an object

59

Define transparent

Material transmits all or almost all incident light

60

Define translucent

Material transmits some incident light but absorbs/reflects the rest

61

Opaque

Material doesn't transmit any incident light

62

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

Opens wider

63

What can an eyelid be compared to?

Windshield wipers

64

What causes people to be near or far sighted?

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

65

What is the iris?

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

66

Lens _____ is changed so the amount of bending is changed

Thickness

67

What is the lens' job?

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

68

Far sighted people...

Focus after the retina

69

Near sighted people...

Focus before the retina