7 Light Grade 12 Reflection and Refraction

The file contains a topic about light

1. Holy Rosary Academy of Las Pinas City
PHILOSOPHY
Education that is founded on love and respect of the SUPREME BEING
superimposes on the learner the values that predicate academic excellence.
VISION
A school for virtue centered leadership.
MISSION
Developing lifelong learners and leaders with character and competence.
SLOGAN
At HRA, every learner is a leader.
OBJECTIVES
1. To guide the learner towards a learning experience with God on top of all undertakings.
2. To inculcate learning and working habits which are essential in the pursuit of excellence and recognition.
3. To maximize physical and mental capabilities of the learner toward attaining self-fulfillment and success.
4. To enhance the learner’s interpersonal and academic skills that would ensure his competency and global competitiveness.

2. HAVE A HAPPY DAY!
Physical Science

3. Learning Goals
Objectives •Virtue
UNDERSTANDING
I forgive myself and
others when I make
mistake.

5. Objectives:
MECHANICS: Describing Motion
•
Describe how the propagation of light, reflection, and
refraction are explained by the wave model and the
particle model of light
•
Explain how the photon concept and the fact that the energy of a
photon is directly proportional to its frequency can be used to
explain why red light is used in photographic dark rooms, why we
get easily sunburned in ultraviolet light but not in visible light, and
how we see colors
•
Cite experimental evidence showing that electrons can behave
like waves
•
Differentiate dispersion, scattering, interference, and diffraction
•
Explain various light phenomena

6. Holy Rosary Academy of Las Pinas City
Foundational Literacies
Howstudents apply core
skills to everyday tasks
Competencies
How students approach
complex challenges
CharacterQualities
How students approach their
changing environment
___Literacy
___ Numeracy
___ Scientific Literacy
___ ICT Literacy
___ FinancialLiteracy
___ Cultural and civic
literacy
___ Critical thinking/problem
solving
___ Creativity
___ Communication
___Collaboration
___ Curiosity
___ Initiative
___ Persistency/grit
___ Adaptability
___ Leadership
___ Social and cultural
awareness
21
st
Century Skills
Lifelong Learning
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8. OPTICS
•The study of the
behavior and
properties of light.
•VISIBLE LIGHT –
only part of the
electromagnetic
spectrum that is
visible to the eyes
in the form of
colors.
•SPEED OF LIGHT

9. The longest the wavelength, the lower its frequency

10. NATURE OF LIGHT

11. NATURE OF LIGHT
Isaac Newton
•Corpuscular or Particle
Theory of Light
Christiaan Huygens
•Wave Theory of Light

12. Aristotle ( Light was emitted from our eyes )
Christian Huygens ( Wave theory of light )
Isaac Newton ( Particle theory of light )
Thomas Young ( Wave theory of light )
Albert Einstein ( Particle theory of light )
de Broglie ( Wave-particle duality of all matter)

13. NATURE OF LIGHT
ChristiaanHuygens
•WaveTheoryofLight
Lightisapropagating
waveinahypothetical
materialcalledether.
Assertsthatlighthasboth
electricalandmagnetic
componentspropagating
inspaceandcanbe
reflectedwhenithitsan
object.

14. NATURE OF LIGHT
IsaacNewton
•CorpuscularorParticle
TheoryofLight
Lightiscomposedof
particlesshootingoutfrom
asource.
Assertsthetheseparticles
collidewithanyobjectand
bounceback,orpass
throughandinteractwith
theatomsoftheobject.

15. The wave theory of
light was widely
accepted until 1905……
Albert Einstein
1879 -1955
Wave theory of
light? “No
way!”

The photoelectric effect is observed when light strikes a metal,
and emits electrons.

Einstein used the idea of photons (light consists of tiny particles)
to explain results which demonstrate the photoelectric effect.

16. PHOTOELECTRIC EFFECT
Heinrich Rudolf Hertz
Happens when electrons
are ejected from an
illuminated metallic
surface, which suggests
that light propagates as a
stream of particles
(photons) rather than as
electromagnetic waves.

17. Albert Einstein provided a piece of convincing
evidence for the particle nature of light ……
Has the story ended yet?
Is light particles or waves?
Louis de Broglie
1892 -1987
Light is not
particles, not
waves, but BOTH!

18. PHOTONS AND
THE ATOMIC SPECTRUM

19. Photons
•Stream of particles (light)
•Characteristics:
Has the same speed as that of
light
( )
Can carry energy and momentum
Can be emitted or absorbed
Can interact with other particles
like electrons
PHOTONS AND THE ATOMIC SPECTRUM

20. Photons
•The form of
energy emitted
by electrons
when they go
back from a
higher energy
level to a lower
energy level
PHOTONS AND THE ATOMIC SPECTRUM

21. Photons
-frequency of photon
-initial energy level
-final energy level
-Planck’s constant
PHOTONS AND THE ATOMIC SPECTRUM

22. Photons
•Einstein supported the idea
that light is a particle
•With Planck’s work,
Einstein suggested that the
energy of the photon is
directly proportional to its
frequency where the
constant of proportionality
is the Planck’s constant.
PHOTONS AND THE ATOMIC SPECTRUM
–energy of photon
-Planck’s constant
–frequency
High frequency light contains
large amounts of energy,
more damaging to matter
than low frequency light

23. •Red light is used in
photographic dark rooms.
-It is aroomthat can be made
completelydarkto allow the
processing of the light-
sensitive photographic
materials, including film and
photographic paper.
-Higher-frequency visible light
is damaging to photographic
films.
PHOTONS AND THE ATOMIC SPECTRUM

24. •The pigments in the skin
also undergo
photochemical reaction
when exposed to UV light.
-UV light has more energy
than the visible light
-UV light causes sunburn
PHOTONS AND THE ATOMIC SPECTRUM

25. PROPERTIES/
BEHAVIOR OF LIGHT

26. BEHAVIOR OF LIGHT
1)Reflection
2)Refraction
3)Total Internal Reflection
4)Transmission and Absorption
5)Dispersion
6)Scattering
7)Diffraction
8)Interference

27. BEHAVIOR OF LIGHT
1)Reflection

28. BEHAVIOR OF LIGHT
1)Reflection
-The bouncing back of light
when it hits a boundary of
another medium
-Principles:
The incident ray, the reflected
ray, and the normal lie on the
same plane.
The angle of incidence is
equal to the angle of
reflection :

29. CONCEPTS TO REMEMBER
> INCIDENT RAY -light that strikes a
surface
> REFLECTED RAY -represents the light
reflected by the surface
> REFRATED RAY -represents the light
refracted (bent) by another medium
> NORMAL LINE –a line perpendicular to
the surface / medium of diff. boundaries

31. BEHAVIOR OF LIGHT
2) Refraction

32. BEHAVIOR OF LIGHT
2) Refraction
-The bending of light caused by the changing
of its speed through different media.
-When light travels through a given
medium, its speed changes.
-Index of Refraction
-Snell’s Law
If light is traveling from a less dense material to
a denser one, the angle of refraction from the
normal is less than the angle of incidence, and
vice versa.

33. Light bends towards the normal line as it passes from
less dense to denser boundaries.

34. Depending on the object, light passes through
differently

35. BEHAVIOR OF LIGHT
3) Total Internal Reflection

36. BEHAVIOR OF LIGHT
3) Total Internal Reflection
-The reflection of the total
amount of incident light at the
boundary between two media
with different densities.
-Requirements:
1)Light must come from the denser medium approaching
the less dense one
2)The angle of incidence must be greater than the critical
angle -the limiting angle of incidence in the denser
medium resulting in an angle of refraction of with
the normal

37. BEHAVIOR OF LIGHT
4) Transmission and Absorption

38. BEHAVIOR OF LIGHT
4) Transmission and Absorption
-Depend on the thickness of the
material and the type of light used.
Thicker objects absorb more light
than thinner ones.
-OPAQUE: Objects that absorb a
particular frequency of light
-TRANSPARENT: Objects that allow
light to pass through materials
without being scattered.
-FILTERS:Transparent materials which
allow selected colors to pass through

39. Different frequencies of visible light correspond
to different colors; either absorbed or reflected
When light hits an object, some of its frequencies
are either absorbed or reflected.

40. BEHAVIOR OF LIGHT
5) Dispersion

41. BEHAVIOR OF LIGHT
5) Dispersion
-The separation of white
light into a spectrum of
colors when it passes
through a prism.
-Occurs because the
refractive index of the
prism is slightly different
for each color.
-Different colors of light
are bent at different
angles.

42. REFRANGABILITY. The capability of light
rays to be refracted.
NEWTON:Color is not a property of an
object but a property of light that
illuminates it.

43. BEHAVIOR OF LIGHT
6) Scattering

44. BEHAVIOR OF LIGHT
6) Scattering
-Occurs when the sunlight
are redirected by the
particles suspended in the
atmosphere (scatterers)
Rayleigh Scattering:When
the sizes of the scatters are
smaller than the wavelength
of light being scattered, light
of short wavelengths (e.g.,
blue, violet) is scattered
more effectively than light of
long wavelengths (e.g., red)

45. BEHAVIOR OF LIGHT
7) Diffraction

46. BEHAVIOR OF LIGHT
7) Diffraction
-The slight bending of light
around barriers
-For it to be noticeable, the
wavelength of light must be
approximately the same or
bigger than the slit or the
opening of the barriers
-Light of longer wavelengths is
diffracted at a smaller angle
than light of shorter
wavelengths.

47. BEHAVIOR OF LIGHT
8) Interference

48. BEHAVIOR OF LIGHT
8) Interference
-Occurs when two waves meet
while travelling through the
same medium
•CONSTRUCTIVE INTERFERENCE :
When two or more waves with
equal phase and frequency
reinforce each other.
•DESCTRUCTIVE INTERFERENCE :
When two or more waves with
opposite phase and equal
frequency interfere and cancel
each other.

49. BEHAVIOR OF LIGHT
1)Reflection
2)Refraction
3)Total Internal Reflection
4)Transmission and Absorption
5)Dispersion
6)Scattering
7)Diffraction
8)Interference

50. OPTICAL PHENOMENA

51. Optical Phenomena
•Reflection on Different Types of
Mirrors
•Mirage
•Haloes and Sun Dogs
•Rainbows
•Clouds
•Blue Sky
•Red Sunsets
OPTICAL PHENOMENA

52. Reflection on Different Types of Mirrors
•Plane Mirror
•Concave Mirror
•Convex Mirror
OPTICAL PHENOMENA

53. Reflection on Different Types of Mirrors
•Plane Mirror
-Law of Reflection
OPTICAL PHENOMENA

54. Reflection on Different Types of Mirrors
•Concave Mirror
•Convex Mirror
OPTICAL PHENOMENA

55. Mirage
•An optical phenomenon that
produces the illusion of water due
to the refraction of light through a
nonuniform medium.
•Created when light passes through
air of different temperatures.
•When an object is viewed from a
very low angle, light from the
object will follow a curved path
toward an observer’s eye.
OPTICAL PHENOMENA
An inferior mirage makes it look like
there is water on the pavement,
when in fact there is not.

56. Haloes and Sun Dogs
•Haloes–formed around the
moon, Sun, or any celestial
light source when there is
enough elevation for cirrus
clouds.
-When light passes through ice
crystals, light is refracted twice,
making from its original
direction.
OPTICAL PHENOMENA
When Sun is seen at , a halo
can be observed.
Light formed around any celestial
light source.

57. Haloes and Sun Dogs
•Sun Dogs–patches of light
that appears beside the Sun.
-Also called “mock Suns” or
parhel(Greek word which
means ‘beside the Sun’)
-Have the same mechanism as
how haloes are formed,
however, they are produced
by hexagonal plate of crystals
with their faces nearly
horizontal
OPTICAL PHENOMENA
The blue light is more refracted than the
red light so the blue light is seen at
the outer edges of the Sun dogs.

58. Rainbows
•When sunlight enters a water
droplet, it is dispersed into
different colors
-These colors are refracted at
slightly different angles: red is
bent the least, violet is bent the
most
-The sunlight then reaches the
back surface of the droplet and
is reflected –primary rainbow.
OPTICAL PHENOMENA

59. Rainbows
OPTICAL PHENOMENA
Secondary rainbow is the spectrum of
colors that escapes when two
reflections happened inside the water
droplet, with colors in reversed order.
Supernumerary bows are often
greenish-purple bows that are closely
located at the inner side of the primary
rainbow, which happens because of the
interference of the wave crests.

60. Clouds
OPTICAL PHENOMENA
White is how our eyes perceive all
wavelengths of sunlight mixed
together.
When it's about to rain, clouds darken
because the water vapor is clumping together
into raindrops, leaving larger spaces between
drops of water. Less light is reflected.
The rain cloud appears black or gray.

61. Blue Sky
•The blue component of the spectrum
of visible light has shorter
wavelengths and higher frequencies
than the red component.
•Thus, as sunlight of all colors passes
through air, the blue part causes
charged particles to oscillate faster
than does the red part.
•The faster the oscillation, the more
scattered light is produced, so blue is
scattered more strongly than red.
OPTICAL PHENOMENA

62. Blue Sky
•Sunlight reaches Earth's
atmosphere and is scattered
in all directions by all the
gases and particles in the
air.
•Blue light is scattered more
than the other colors
because it travels as shorter,
smaller waves.
OPTICAL PHENOMENA

63. Red Sunsets
•Within the visible range of
light, red light waves are
scattered the least by
atmospheric gas molecules.
•At sunrise and sunset, when
the sunlight travels a long path
through the atmosphere to
reach our eyes, the blue light
has been mostly removed,
leaving mostly red and yellow
light remaining.
OPTICAL PHENOMENA

64. Red Sunsets
•As the Sun gets lower in the
sky, its light is passing
through more of the
atmosphere to reach you.
•Even more of the blue light
is scattered, allowing the
reds and yellows to pass
straight through to your
eyes.
OPTICAL PHENOMENA

65. SUBMISSION: Today
Tabulation of Eval Scores
Eval No. Score/No. of Items
1
-
7
TOTAL SCORE:Total Score/Total No. of Items

66. HEADS UP!

67. REMINDER: HEADS UP!Quiz No. 1 –deployed: MONDAY (Apr. 19 -21)
-Early views of Motion, and Concept of Motion
-VSMART LMS
FLA NO. 1: Optics (Submission: Until Apr. 25)
Unit Test –deployment: FRIDAY (Apr. 23)
-Early Views of the Universe, Concept of Motion, Light
-recorded as Quarter Exam score, VSMART LMS
Project–Compilation, on or BEFORE FRIDAY (Apr. 30)
-Notes
-WORKS
-Reflection
67

68. FLA No. 1 Light

69. 69
FLA No. 1 Light

70. Learning Goals
Objectives •Virtue
UNDERSTANDING
I show empathy and
compassion.

71. 4
TH
QUARTER
PHYSICAL SCIENCE
HAVE A
HAPPY DAY!