Senior High School
NOT
General Physics 2
Quarter 4 - Module 2/ Week 8
Electromagnetic Waves and the Nature &
Propagation of Light
Department of Education ● Republic of the Philippines
General Physics 2 – Grade 12
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Quarter 4 – Module 2:
Electromagnetic Waves and the Nature & Propagation of Light
First Edition, 2020
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Senior
High
School
Senior
High
School
General Physics 2
Quarter 4 - Module 2/ Week 8:
Electromagnetic Waves and the Nature &
Propagation of Light
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Table of Contents
What This Module is About .................................................................................................... i
What I Need to Know ............................................................................................................. i
How to Learn from this Module............................................................................................. ii
Icons of this Module .............................................................................................................. ii
What I Know ......................................................................................................................... .iv
Lesson 1: Light as an Electromagnetic Wave
What’s In ..................................................................................................................................... 1
What I Need to Know .................................................................................................................. 1
What’s New: ................................................................................................................................ 2
What Is It ..................................................................................................................................... 5
What’s More: ............................................................................................................................... 6
What I Have Learned: ................................................................................................................. 7
Lesson 2: Total Internal Reflection
What’s In ..................................................................................................................................... 8
What I Need to Know .................................................................................................................. 9
What’s New: ................................................................................................................................ 9
What Is It ..................................................................................................................................... 10
What I Have Learned: ................................................................................................................. 12
Lesson 3: Polarization (Malus’s Law)
What’s In ..................................................................................................................................... 13
What Is It ..................................................................................................................................... 13
What I Have Learned: ................................................................................................................. 14
Summary ............................................................................................................................. 15
Assessment: (Post-Test) .................................................................................................... 16
Key to Answers ................................................................................................................... 17
References .......................................................................................................................... 18
i
Module 2
Light as an Electromagnetic Wave
What This Module is About
This module provides you with explanation of electromagnetic waves differ from
mechanical waves in that they do not require a medium to propagate. This means that
electromagnetic waves can travel not only through air and solid materials, but also
through the vacuum of space.
Electricity can be static, like the energy that can make your hair stand on end.
Magnetism can also be static, as it is in a refrigerator magnet. A changing magnetic
field will induce a changing electric field and vice-versa the two are linked. These
changing fields form electromagnetic waves.
The lessons in this module are necessary and essential in studying other
concepts in the next modules.
The following are the lessons contained in this module:
•
•
•
Lesson 1- Light as an electromagnetic Wave
Lesson 2- Total Internal Reflection
Lesson 3- Polarization (Malus’s Law)
What I Need to Know
In this module, you are expected to:
1. Relate the properties of EM wave (wavelength, frequency, speed) and the
properties of vacuum and optical medium (permittivity, permeability, and index
of refraction) STEM_GP12OPTIVb-12
2. Explain the conditions for total internal reflection STEM_GP12OPTIVb-14
3. Explain the phenomenon of dispersion by relating to Snell’s Law
STEM_GP12OPTIVb-16
4. Calculate the intensity of the transmitted light after passing through a series of
polarizers applying Malus’s Law STEM_GP12OPTIVc-18
5. Solve problems involving reflection, refraction, dispersion, and polarization in
contexts such as, but not limited to, (polarizing) sunglasses, atmospheric
haloes, and rainbows STEM_GP12OPTIVc-21
ii
Icons of this Module
How to Learn from this Module
To achieve the learning competencies cited above, you are to do the following:
•
•
•
Take your time reading the lessons carefully.
Follow the directions and/or instructions in the activities and exercises diligently.
Answer all the given tests and exercises.
iii
What I Know
MULTIPLE CHOICES. Directions: Read and understand each item and choose the
letter of the correct answer. Write your answers on your Science activity notebook.
1. What do all the types of radiation have in common?
a. amplitude
c. speed
b. frequency
d. wavelength
2. How can you tell one form of electromagnetic energy from another?
a. wavelength
c. amplitude
b. color
d. speed
3. On rotating the analyzer if the intensity of light rays coming out of it varies from
maximum to zero, then the incident beam of light is ________.
a. un-polarized
c. partially polarized
b. plane polarized
d. polarized
4. Which one of the following cannot be polarized?
a. sound waves
b. X-rays
5. Light waves are ___________.
c. microwaves
d. radio waves
a. longitudinal
b. like pressure waves
c. like sound waves
d. transverse
6. The speed of light is closest to
a. 3,000,000 m/s
c. 300,000,000 m/s
b. 30,000,000 m/s
d. 3,000,000,000 m/s
7. The region of the electromagnetic spectrum where humans can detect
electromagnetic radiation is
a. visible
c. ultraviolet
b. infrared
d. x-ray
8. It is a law that applies only if the incident light passing through the analyzer is nearly
polarized.
a. Malus’s Law
c. Law of Reflection
b. Refraction Law
d. Snell’s Law
9. What is polarized light?
a. when waves oscillates in one direction
b. where waves oscillates in one plane
c. where electric field component oscillates in one plane
d. where magnetic field component oscillates in one plane.
10. A polarized light of intensity Io is passed through another polarizer whose pass axis makes
an angle of 60o with the pass axis of the former. What is the intensity of emergent polarized
light from second polarizer?
a. I = I0
c. I = I0 / 5
b. I = I0 / 6
d. I = I0 / 4
iv
Lesson
1
Light as an Electromagnetic
Wave
This lesson will explore the different types of electromagnetic waves and how
electromagnetic waves differ from mechanical waves in that they do not require a
medium to propagate. This means that electromagnetic waves can travel not only
through air and solid materials, but also through vacuum of space.
The learner is expected to summarize the relationship between electricity and
magnetism into what are now referred to as “Maxwell’s equation” by Scottish scientist
named James Maxwell.
What’s In
Directions: Try to arrange the following jumbled words. The
descriptions provided below will help you unlock this task. Write your answers in your
Science notebook.
NCYEQUEFR
1. the number of occurrences of a
repeating event per unit of time.
NGTHVELEWA
2. distance between corresponding
points of two consecutive waves
ISMMAGNET
3. a class of physical phenomena that
are mediated by magnetic field.
ETISMELECMAGNTRO
4. a branch of physics which involves
the study of electromagnetic force.
NETICELEOMAGCTR TRUMECSP
5. the range of all types of EM radiation
What I Need to Know
After this lesson, you should be able to:
1. Relate the properties of EM wave (wavelength, frequency, speed) and the
properties of vacuum and optical medium (permittivity, permeability, and index
of refraction) STEM_GP12OPTIVb-12
1
What’s New
Electromagnetic waves
Electromagnetic waves are transverse waves with a wide range of properties
and uses. Some of the waves are also hazardous to human body tissues. Their
vibrations or oscillations are changes in electrical and magnetic fields at right angles
to the direction of wave travel. Electromagnetic waves travel at 300,000,000 meters
per second (m/s) through a vacuum.
All electromagnetic waves:
•
•
•
transfer energy from the source of the waves to an absorber.
can travel through a vacuum such as in space.
all travel at the same velocity through a vacuum.
Electromagnetic spectrum
Electromagnetic waves form a continuous spectrum of waves. This includes:
•
waves with a very short wavelength, high frequency and high energy
•
waves with a very long wavelength, low frequency and low energy
Electromagnetic waves can be separated into seven distinct groups in the spectrum.
source: https://tinyurl.com/18eotfwb
Each group contains a range of frequencies. For example, visible light contains all
the frequencies that can be detected by the human eye:
•
red light has the lowest frequencies of visible light
•
violet light has the highest frequencies of visible light
2
The behavior of an electromagnetic wave in a substance depends on
its frequency or wavelength. The differing behaviors of different groups in the
electromagnetic spectrum make them suitable for a range of uses.
All electromagnetic waves are light, but the band of the electromagnetic
spectrum that people and animals can see is called visible light. When a beam of light
passes through a prism, a person can see each colour of the rainbow separated into
their individual wavelengths.
Source: https://tinyurl.com/y9wrjf9n
Red, the longest of the wavelengths, measures around 700 nanometers; yellow
is around 600 nanometers; and violet, the shortest, is around 400 nanometers in
length.
3
Describing Electromagnetic Energy
The terms of light, electromagnetic waves, and radiation all refer to the same physical
phenomenon: electromagnetic energy. This energy can be described by frequency,
wavelength, or energy. All three are related mathematically such that if you know
one, you can calculate the other two. Radio and microwaves are usually described in
terms of frequency (Hertz), infrared and visible light in terms of wavelength (meters),
and x-rays and gamma rays in terms of energy (electron volts). This scientific
convention that allows the convenient use of units that have numbers that are neither
too large nor too small.
Frequency
The number of crests that pass a given point within one second is described as the
frequency of the eave. One wave – one cycle – per second is called a Hertz(Hz), after
Heinrich Hertz who established the existence of radio waves. A wave with two cycles
that pass a point in one second has a frequency of 2 Hz.
Wavelength
Electromagnetic waves have crests and troughs similar to those of ocean waves. The
distance between crests is the wavelength. The shortest wavelengths are just fractions
of the size of an atom, while the longest wavelengths scientists currently study can be
larger than the diameter of our planet.
Energy
An electromagnetic wave can also be described in terms of its energy – in units of
measure called electron volts (eV). An electron volt is the amount of kinetic energy
needed to move an electron through one-volt potential. Moving along the spectrum
from long to short wavelengths, energy increases as the wavelength shortens.
Consider a jumping rope with its ends being pulled up and down. More energy is
needed to make the rope have more waves.
source: https://tinyurl.com/57flkesn
4
What Is It
Maxwell’s Synthesis of Electricity of Electricity, Magnetism and
Optics
In 1873, seventy years after Thomas Young presented his experimental results
on the nature of light, a Scottish physicist named James Clerk Maxwell published
a theory that accounted for the physical origins of light. Throughout the nineteenth
century, many of science's greatest minds dedicated themselves to the study of two
exciting new ideas: electricity and magnetism. Maxwell's work synthesized these two
ideas, which had previously been considered separate phenomena. His new theory
was aptly named a theory of “electromagnetism”.
Maxwell and other physicists began exploring their implications and testing their
predictions. One prediction that came from Maxwell's equations was that
a charge moving back and forth in a periodic fashion would create an oscillating
electric field. This electric field would then set up a periodically changing magnetic
field, which in turn would cause the original electric field to continue its oscillation, and
so on. This mutual vibration allowed the electric and magnetic fields to travel through
space in the form of an "electromagnetic wave," as shown below:
source: https://tinyurl.com/1gpyszoy
Because this new mathematical model of electromagnetism described a wave,
physicists were able to imagine that electromagnetic radiation could take on the
properties of waves. Thus, just like all waves, Maxwell's electromagnetic waves could
have a range of wavelengths and corresponding frequencies.
This range of wavelengths is now known as the "electromagnetic spectrum."
Maxwell's theory also predicted that all the waves in the spectrum travel at a
characteristic speed of approximately 300,000,000 meters per second. Maxwell was
able to calculate this speed from his equations:
𝒄=
𝟏
√𝜺 𝒐 𝝁𝒐
= 𝟐. 𝟗𝟗𝟖 × 𝟏𝟎𝟖 𝒎/𝒔
Where ,
c= speed of the electromagnetic wave
𝜺𝒐 = permittivity of free space (8.854×10−12 F/m)
𝝁𝒐 = permeability of free space (4π×10−7 N/A2 )
5
Maxwell's calculation of the speed of an electromagnetic wave included two
important constants: the permittivity and permeability of free space.
The permittivity of free space is also known as the "electric constant" and
describes the strength of the electrical force between two charged particles in a
vacuum. The permeability of free space is the magnetic analogue of the
electric constant. It describes the strength of the magnetic force on an object in a
magnetic field.
Thus, the speed of an electromagnetic wave comes directly from a fundamental
consideration of electricity and magnetism.
When Maxwell calculated this speed, he realized that it was extremely close to the
measured value for the speed of light, which had been known for centuries from
detailed astronomical observations. After Maxwell's equations became widely known,
the Polish-American physicist Albert Michelson made a very precise measurement of
the speed of light that was in extremely close agreement with Maxwell's predicted
value. This was too much for Maxwell to accept as coincidence and led him to the
realization that light was an electromagnetic wave and thus part of the
electromagnetic spectrum.
What’s More
Activity 1: Comprehension Checkpoint
1. Microwaves, gamma rays, radio waves are all types of __________________.
2. Light consists of oscillating ______________ and _______________ fields.
3. Light in a vacuum always moves at roughly ________________ m/s.
4. One piece of evidence that convinced Maxwell that light was electromagnetic
radiation was…
a.
light can generate electrical currents.
b.
a moving magnetic field can generate light.
c.
the speed of light is the same as the speed of sound.
d.
the measured speed of light was close to Maxwell's calculated speed.
6
What I Have Learned
Directions: Identify the term/s being referred to in each blank. Choose
from the box your answer. Write you answer in your Science notebook.
Electromagnetic waves are ______________ waves with a wide range of
properties and uses. EM waves can travel not only through air and solid materials, but
also through ____________ of space. Electromagnetic waves can be separated into
seven distinct groups in the______________. The behavior of an electromagnetic
wave in a substance depends on its _____________ or _____________. Maxwell's
calculation of the speed of an electromagnetic wave included two important constants:
the _______________ and _______________ of free space. The speed of an
electromagnetic wave comes directly from a fundamental consideration of
______________ and ________________.
transverse
vacuum
spectrum
magnetism
permeability
frequency
wavelength
permittivity
electricity
7
Lesson
Total Internal Reflection
2
A light wave does not just stop when it reaches the end of the medium. Rather,
the light wave undergoes certain behaviors when it encounters the end of the medium
- such behaviors include reflection, transmission/refraction, and diffraction. For this
lesson, we will investigate the connection between light reflection and light refraction.
What’s In
ACTIVITY 2: Word Hunt!
Directions: Form a word out of the given number in sequence based on
the numbers corresponding to the letters in the alphabet inside the box below. A
description is already provided for you to easily come up with the name asked. Write
the answer in your Science activity notebook.
A–1
B–2
C–3
D–4
E–5
F–6
G–7
H–8
O – 15
V – 22
I–9
P – 16
W – 23
J – 10
Q – 17
X – 24
K – 11
R – 18
Y – 25
L – 12
S – 19
Z – 26
M – 13
T – 20
N – 14
U – 21
Example:
Description: It is a ray of light that strikes a surface
Code:
9-14-3-9-4-5-14-20
18-1-25
Answer:
INCIDENT
RAY
1. Description:
A law states that when a light ray reflects off a surface, the
angle of incidence is equal to the angle of reflection.
Code:
Answer:
12-1-23
________
15-6
______
18-5-6-12-5-3-20-9-15-14
______________________
2. Description: A law states that when a light ray is transmitted into a new medium,
the relationship between the angle of incidence and the angle of
refraction is given by the following equation ni•sine(Θi) = nr • sine(Θr)
Code:
Answer:
19-14-5-12-12-‘-19
_____________
8
12-1-23
_______
What I Need to Know
After this lesson, you should be able to:
1. Explain the conditions for total internal reflection STEM_GP12OPTIVb-14
2. Explain the phenomenon of dispersion by relating to Snell’s Law
STEM_GP12OPTIVb-16
What’s New
ACTIVITY 3: Complete Me!
Directions: Use the diagram to complete the chart with the needed information. The
first item has been completed for you as an example. Write your answers in your
Science activity notebook.
Label
1
2
Name
incident ray
It is a ray of light that strikes a surface
normal line
3
It is the ray that points in the direction that the
reflected waves are traveling.
4
refracted ray
5
angle of
incidence
6
Description
It is the angle between the reflected ray and the
normal line
9
7
the angle between the refracted ray and the normal
line
8
It is the point where the incident ray strikes the
boundary
What Is It
A light wave, like any wave, is an energy-transport phenomenon. A light
wave transports energy from one location to another. When a light wave strikes a
boundary between two distinct media, a portion of the energy will be transmitted into
the new medium and a portion of the energy will be reflected off the boundary and stay
within the original medium. The actual percentage of energy that is transmitted and
reflected is dependent upon several variables; these will be discussed as we go along
with this lesson. For now, our concern is to review and internalize the basic concepts
and terminology associated with boundary behavior.
Reflection of a light wave involves the bouncing of a light wave off the
boundary, while refraction of a light wave involves the bending of the path of a light
wave upon crossing a boundary and entering a new medium. Both reflection and
refraction involve a change in direction of a wave, but only refraction involves a change
in medium.
The fundamental law that governs the reflection of light is called the law of
reflection. Whether the light is reflecting off a rough surface or a smooth surface, a
curved surface or a planar surface, the light ray follows the law of reflection. The law
of reflection states that “When a light ray reflects off a surface, the angle of incidence
is equal to the angle of reflection.”
The fundamental law that governs the refraction of light is Snell's Law. Snell's
Law states that “When a light ray is transmitted into a new medium, the relationship
between the angle of incidence (Θi) and the angle of refraction (Θr) is given by the
following equation:
ni • sine(Θi) = nr • sine(Θr)
Equation 1
where the ni and nr values represent the indices of refraction of the incident and the
refractive medium, respectively.
A common Physics lab is to sight through the long side of an isosceles triangle
at a pin or other object held behind the opposite face. When done so, an unusual
observation - a discrepant event - is observed. The diagram on the left below depicts
the physical situation. A ray of light entered the face of the triangular block at a right
angle to the boundary. This ray of light passes across the boundary without refraction
since it was incident along the normal. The ray of light then travels in a straight line
through the glass until it reaches the second boundary. Now instead of transmitting
10
across this boundary, all of the light seems to reflect off the boundary and transmit out
the opposite face of the isosceles triangle.
This discrepant event bothers many as they spend several minutes looking for
the light to refract through the second boundary. Then finally, to their amazement, they
looked through the third face of the block and clearly see the ray. What happened?
Why did light not refract through the second face?
Image source: https://tinyurl.com/25xgecfr
The phenomenon observed in this part of the lab is known as total internal
reflection. Total internal reflection (TIR) is the reflection of the total amount of
incident light at the boundary between two media.
To understand total internal reflection, let us consider this fiber optic cable.
image source: https://tinyurl.com/ggs5uwnm
An optic fiber cable is made up of thin strands of glass or plastic. These strands
carry information between two places in a form of light. As you know, glass is a dense
medium that refracts light, but light does not refract light inside the fiber optic cable.
Do you know why the incident ray did not refract here? We can understand the
reasons for this once we understand the process of total internal reflection.
A ray of light passing from a dense medium into a rear medium refracts and
bends away from the normal line. The angle of refraction is greater than the angle of
incidence. When the angle of refraction is equal to 90 degrees, we get a critical angle.
In this case, the angle of incidents is equal to the critical angle but when the angle of
incidence becomes greater than the critical angle then, the refracted ray does not enter
the rear medium rather, it is reflected in the same medium. This is what we call the
TOTAL INTERNAL REFLECTION.
11
Going back to the example of the optical fiber, the light rays hit the inside
surface of the wall of the optical fiber at an angle greater than the critical angle, due to
this, the light ray reflects with the same medium.
Remember, there are two necessary conditions for total internal reflection do happen.
o the ray of light must be traveling from a dense medium to a rare medium.
o the angle of incidence must be greater than the critical angle.
Image source: https://tinyurl.com/25xgecfr
Many optical instruments use the principle of total internal reflection. Total
internal reflection is used in instrument such as fiber optic, binoculars, and periscope.
What I Have Learned
Activity 4: Check Your Understanding…
1. For each combination of media, which light ray (A or B) will undergo total
internal reflection if the incident angle is gradually increased? Write your answer in
your Science activity notebook.
Image source: https://tinyurl.com/25xgecfr
12
Lesson
3
Polarization
(Malus’s Law)
What’s In
When light falls on a polarizer, the transmitted light gets polarized. The polarized
light falling on another Polaroid, called analyzer, transmits light depending on the
orientation of its axis with the polarizer. The intensity of light transmitted through the
analyzer is given by Malus' law.
For this lesson, we will calculate the intensity of the transmitted light after passing
through a series of polarizers applying Malus’s Law.
What Is It
How does a polarizer work?
Polarizers are usually made out of oblong shaped molecules, all aligned in the
same direction. It turns out that if the polarization of the incident beam is the same as
alignment orientation, then the light is most likely to be absorbed. If the polarization is
perpendicular to the long axis of molecules, then it is transmitted almost entirely and
that direction is the axis of the polarizer. If the angle of polarization is something in
between, it passes through only partially and its initial irradiance decreases. The exact
value can be determined thanks to the Malus law.
Image source: https://tinyurl.com/3damm3ex
13
Malus Law Formula
The intensity (I) of polarized light after passing through a polarizing filter is
usually measured in 𝑊/𝑚2 . The light intensity, which passes through the ideal
polarizer can be calculated as:
I = I0 cos2 θ
Equation 2
Where, I0 is the initial intensity of light and θ is the angle between the direction
of polarization and the axis of the filter.
Example: Intensity of Light Changes under rotation.
Let us say that you want to check how the intensity of polarized light changes,
while you rotate your polarizer.
1. Choose a few different values of the axis of polarizer orientation with respect
to the polarization of incident rays, e.g. θ₁=20°, θ₂=45°, θ₃=70°,
2. Determine cosθ of this angles, which are 0.939, 0.707, 0.342 respectively,
3. Find squares of this values: 0.883, 0.5, 0.117,
4. Multiply them by the initial intensity, say I₀=5 W/m²: I₁=4.415 W/m², I₂=2.5
W/m², I₃=0.585 W/m²...
You can always express obtained results as the percentages of initial intensity.
What I Have Learned
Activity 3.7: Problem Solving
Direction: Solve the following problems. Show your complete solutions legibly and
concisely in your Science activity notebook.
1. A polarized light of intensity I0 is passed through another polarizer whose pass axis
makes an angle of 60 degrees with the pass axis of the former. What is the intensity
of emergent polarized light from second polarizer?
2. What angle is needed between the direction of polarized light and the axis
of a polarizing filter to reduce its intensity by 90.0%?
14
Summary
•
Electromagnetic waves are transverse waves with a wide range of properties
and uses.
•
Electromagnetic waves travel at 300,000,000 meters per second (m/s)
through a vacuum.
•
Maxwell's calculation of the speed of an electromagnetic wave included two
important constants: the permittivity and permeability of free space.
•
Maxwell’s prediction of electromagnetic waves resulted from his formulation
of a complete and symmetric theory of electricity and magnetism, known as
Maxwell’s equations.
•
Reflection of a light wave involves the bouncing of a light wave off the
boundary, while refraction of a light wave involves the bending of the path of
a light wave upon crossing a boundary and entering a new medium.
•
The intensity of light transmitted through the analyzer is given by Malus' law.
•
Light can be polarized by passing it through a polarizing filter or other
polarizing material. The intensity I of polarized light after passing through a
polarizing filter is I = I0 cos2 θ, where I0 is the original intensity and θ is the
angle between the direction of polarization and the axis of the filter.
Congratulations! You have completed Module 2. Please proceed
to Module 3 and learn about the Geometric Optics.
15
Assessment:
MULTIPLE CHOICES. Directions: Read and understand each item and choose the
letter of the correct answer. Write your answers on your Science activity notebook.
1. Three polarized are placed such that, the first and the third are mutually
perpendicular to each other. Unpolarized light of intensity Io is incident or first
polarized. The intensity of light emerging from the third polaroid’s is (1/16) of
the intensity of incident light. Find the angle between first the angle between
first and second polaroid’s.
A. α= 24.5o
B. α= 25.6o
C α= 30.5o
. D. α= 31.5o
2. For our purposes, it is sufficient to merely say that an electromagnetic wave is
a transverse wave that has both an
A. electric and a magnetic component C. electric and wave component
B. sound and magnetic waves
D. sound and electric component
3. The use of two filters, one can completely block all of the light that is incident
upon the set; this will only occur if the polarization axes are rotated such that
they are :
A. Parallel to each
C. Opposite to each other
B. perpendicular to each other.
D. near each other
4. What will happened if you hold a polarized sunglass in front of you and rotate
them. While looking at the blue sky, you will see the sky get _____
A. brighter
B. dimmer
C. invisible
D. brighter and dimmer
5. 5. What happens when two polarizing filters are placed so that their axes of
polarization. Are perpendicular to each other?
A. Transmitted light is slightly weaker C. transmitted light are polarized.
B. There is no transmitted light
D. Transmitted light oscillates in all direction.
6. What do all the types of radiation have in common?
a. amplitude
c. speed
b. frequency
d. wavelength
7. How can you tell one form of electromagnetic energy from another?
a. wavelength
c. amplitude
b. color
d. speed
8. On rotating the analyzer if the intensity of light rays coming out of it varies from
maximum to zero, then the incident beam of light is ________.
a. un-polarized
c. partially polarized
b. plane polarized
d. polarized
e.
9. Which one of the following cannot be polarized?
a. sound waves
c. microwaves
b. X-rays
d. radio waves
10. Light waves are ___________.
a. longitudinal
c. like sound waves
b. like pressure waves
d. transverse
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LESSON 2
1. Description:
Code:
Answer:
2. Description:
Code:
Answer:
A law states that when a light ray reflects off a surface, the angle of incidence is equal to
the angle of reflection.
12-1-23 15-6
18-5-6-12-5-3-20-9-15-14
LAW OF
REFLECTION
A law states that when a light ray is transmitted into a new medium, the relationship between the
angle of incidence and the angle of refraction is given by the following equation ni•sine(Θi) = nr •
sine(Θr)
19-14-5-12-12-‘-19
SNELL’S
LAW
12-1-23
CHECK YOUR UNDERSTANDING ANSWER
Practice A: Light ray A is in the more dense medium and it will be the one which will undergo TIR.
Practice B: Light ray A is in the more dense medium and it will be the one which will undergo TIR.
Lesson 2
Label
Name
1
incident ray
Lesson 1
Description
It is a ray of light that strikes a surface
WHAT’S MORE
It is the point where the incident ray strikes the
boundary
point of
incidence
8
the angle between the refracted ray and the normal line
angle of
refraction
7
It is the angle between the reflected ray and the normal
line
angle of
reflection
6
It is the angle between the incident ray and the normal
line
angle of
incidence
5
It is the ray that points in the direction that the refracted
waves are traveling.
refracted ray
4
It is the ray that points in the direction that the
reflected waves are
traveling.
reflected ray
3
It is always drawn perpendicular to the surface at the
point of incidence.
normal line
2
1. electromagnetic radiation
2. electric & magnetic
3. 300,000,000
4. D
WHAT I HAVE LEARNED
1.
2.
3.
4.
5.
6.
7.
8.
9.
LESSON 3
1. I=Io/4
2. 71.6º.
Transverse
Vacuum
Spectrum
frequency
wavelength
permittivity
permeability
electricity
magnetism
LESSON 1
ASSESSMENT
1.A
2.A
3.B
4.D
5.A
6.C
7.A
8.C
9.A
10.D
WHAT’S IN
What I know
Down
1. FREQUENCY
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
2. WAVELENGHT
3. MAGNETISM
4. ELECTROMAGNETISM
5. ELECTROMAGNETIC
SPECTRUM
c
a
c
a
d
c
a
a
a
d
KEY TO ANSWERS
References
Book Resources________________________________________________
•
•
•
•
•
•
Young, H., Freedman, R., Ford, A., & Young, H. (2012). Sears and Zemansky's University
physics. Boston, MA: Pearson Learning Solutions.
Baltazar and Tolentino. Exploring Life Through Science General Physics 1. Teachers
Wraparound Edition. Phoenix Publishing House, Inc., 2017
Serway / Jewett. Physics for Scientists & Engineers with Modern Physics. Cengage 2014.
Hewitt, Paul. Conceptual Physics. 9th ed. Reprint, Singapore: Pearson Education, 2002
Navaza, Delia, and Bienvenido Valdes. You And The Natural World Physics. 3rd ed. Reprint,
Quezon City: Phoenix Publishing House, Inc., 2010
Zitzewitz, Haase, and Harper. Physics Principles & Problems. Reprint, United States of
America: McGraw-Hill Companies Inc., 2013.
Electronic Resources_____________________________________________
•
Nathaniel Page Stites, M.A./M.S. “Light and Electromagnetism” Visionlearning Vol. PHY-1 (4),
2007, https://www.visionlearning.com/en/library/Physics/24/Light-and
•
Electromagnetism/138/reading, Accessed February 8, 2021
Lumen
Learning
Physics
Textbook: https://courses.lumenlearning.com/physics/,
https://courses.lumenlearning.com/labmethods/chapter/the-electromagnetic-spectrum/,
Accessed February 8, 2021
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