This is the Physical Science Quarter 2 Module 5, “Wave Properties of Light,” a Senior High School self-learning module (Alternative Delivery Mode) for Grade 11 and Grade 12 learners. It was developed by the Department of Education National Capital Region (First Edition, 2020) and written by Helen Grace L. Cabalag. After working through it, learners should be able to explain why electrons can behave like waves and tell apart four wave properties of light: dispersion, scattering, interference, and diffraction.
On this page 7 sections
What learners will learn
Content standard: The learners demonstrate an understanding of light as a wave and as a particle.
Performance standard: The learners should be able to design and create a useful product for practical purposes that uses mirrors and lenses.
Learning competencies:
- Cite experimental evidence showing that electrons can behave like waves (S11/12PS-IVg-64)
- Differentiate dispersion, scattering, interference, and diffraction (S11/12PS-IVh-65)
By the end of the module, learners are expected to:
- Identify the experimental evidence proving that electrons behave as waves.
- Determine the significant explanations regarding the electron double-slit experiment.
- Differentiate dispersion, scattering, interference, and diffraction.
Lessons in this module
- Lesson 1: Wave Behavior of Electrons. Reviews the dual nature of light, then shows how the double-slit experiment gives evidence that electrons also behave like waves.
- Lesson 2: Wave Properties of Light. Explains dispersion, scattering, interference (constructive and destructive), and diffraction, starting with a short poem that describes each property.
Lesson 1: Electrons as particles and waves
The lesson opens with a puzzle. J. J. Thomson won a Nobel Prize for discovering the electron, the first subatomic particle found. His son, George Thomson, won a Nobel Prize for showing the wave properties of the electron by diffraction. So is the electron a particle or a wave?
The module’s answer: just like light, the electron is both a particle and a wave. It has a definite mass and charge, which fits the picture of a particle. The evidence for its wave behavior is the double-slit experiment:
- Electrons are fired at a barrier with two narrow slits, either all at once or one at a time.
- A detector screen behind the slits records where they land.
- The screen shows an interference pattern, a series of alternating bright and dark bands. This pattern is a trait of waves, not of particles.
Scientists first thought the pattern came from electrons bumping into each other. So they sent electrons one at a time, but the same pattern still appeared. This shows that an electron travels as a wave.
The hands-on activity compares this with sand. Learners pour sand through two slits cut 1.0 cm apart in a paper cup. The sand simply piles up, and grains that arrive at the same spot collide. Electrons, in contrast, build up an interference pattern.
Lesson 2: Four wave properties of light
| Property | What happens | Example from the module |
|---|---|---|
| Dispersion | White light separates into a spectrum of colors through refraction | White light through a glass prism splits into ROYGBIV; violet bends the most, red bends the least |
| Scattering | Light rays deviate from their path because of non-uniformities in the medium | Dust particles, gas molecules, and droplets in the air |
| Interference | Two light waves meet while traveling in the same medium and combine (superposition principle) | Bright and dark bands; waves get bigger or smaller |
| Diffraction | Light spreads out as it passes through an opening or around a barrier | Light through a slit makes a wider stream; the smaller the slit, the greater the effect |
Constructive and destructive interference
- Constructive interference happens when two waves have displacements in the same direction. A crest meeting a crest makes a “super-crest,” and a trough meeting a trough makes a “super-trough.” The intensity increases. If two waves of the same amplitude add constructively, the amplitude doubles.
- Destructive interference happens when the waves have opposite displacements, such as a crest meeting a trough. The resulting displacement decreases.
How to use this module
Each lesson follows the usual parts: What I Need to Know, What I Know (pretest), What’s In, What’s New, What is It, What’s More, What I Have Learned, What I Can Do, Assessment, and Additional Activities.
- Answer the 15-item What I Know pretest first. If you get every item right, the module says you may skip it.
- Read each lesson’s discussion, then do the What’s More activities: the sand-and-paper-cup experiment and the electron double-slit questions in Lesson 1, and identifying properties of light from ray diagrams in Lesson 2.
- Fill in the What I Have Learned sentences to sum up the key ideas.
- Do What I Can Do, “The World of Colors,” in a dark room using a flashlight, red, green, and blue Lego blocks, and colored cellophane.
- Take the 15-item Assessment, then try the Additional Activities: the “Rainbow CD” prism and “Waves, Let’s Meet,” where you draw the result of two waves combining.
For learners: Write your answers on a separate sheet of paper, not on the module. Check your work honestly with the answer key at the end, and return the module to your teacher when you finish.
For parents: The experiments use simple home materials such as a paper cup, sand, a flashlight, cellophane, and an old CD. Your child may need help with cutting the slits and setting up a dark room.
For teachers: The module asks facilitators to orient learners on how to use it, track their progress, and support them as they work. The answer key covers the pretest, the What’s More activities, and the assessment.
Frequently asked questions
What grade and quarter is this Physical Science module for?
It is Physical Science Quarter 2 Module 5 for Senior High School, labeled for Grade 11/12 learners.
What lessons are in the Wave Properties of Light module?
It has two lessons: Lesson 1, Wave Behavior of Electrons, and Lesson 2, Wave Properties of Light, which covers dispersion, scattering, interference, and diffraction.
What experiment shows that electrons behave like waves?
The double-slit experiment. Electrons passing through two narrow slits form an interference pattern of alternating bright and dark bands on a screen, even when they are fired one at a time.
Does the module have an answer key?
Yes. The answer key at the end gives answers to the What I Know pretest, the What’s More activities of both lessons, and the 15-item assessment.
Which color bends the most and which bends the least in dispersion?
According to the module, when white light passes through a glass prism, violet bends the most and red bends the least.
Full text of the module
The text below is a transcription of the PDF above, as printed.
Physical Science Quarter 2 – Module 5: Wave Properties of Light
Senior High School
[illustration: teachers and learners studying outdoors and at a desk, with a globe, a lamp, and a sheet of exercises]
GOVERNMENT PROPERTY NOT FOR SALE
Personal Development Alternative Delivery Mode Quarter 2– Module 5: Wave Properties of Light First Edition, 2020
Republic Act 8293, section 176 states that: No copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit. Such agency or office may, among other things, impose as a condition the payment of royalties.
Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this module are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them.
Published by the Department of Education Secretary: Leonor Magtolis Briones Undersecretary: Diosdado M. San Antonio
Development Team of the Module
Authors: Helen Grace L. Cabalag
Editors: Joey H. Villanueva, Arlene C. Malaybalay
Reviewers: Tommy R. Rico, Emiterio D. Macarubbo, Maricris N. Surigao
Illustrator: Helen Grace L. Cabalag
Layout Artist: Justine C. Montoya
Management Team: Wilfredo E. Cabral, Director IV Jennifer F. Vivas, CLMD Chief Dennis M. Mendoza, Regional EPS in-charge of LRMS Micah S. Pacheco, Regional ADM Coordinator Jocelyn M. Aliñab, CID Chief Tommy R. Rico, Division in-charge of LRMS and Division ADM Coordinator
Department of Education – National Capital Region
Office Address: Misamis St., Bago Bantay, Quezon City
Telefax: 02-929-0153
E-mail Address: depedncr@deped.gov.ph
Senior High School
Physical Science Quarter 2 – Module 5: Wave Properties of Light
Introductory Message
For the facilitator:
Welcome to Physical Science Grade 11/12 Alternative Delivery Mode (ADM) Module on Wave Properties of Light!
This module was collaboratively designed, developed, and reviewed to assist the teachers/facilitators in helping the learners meet the standards set by the K to 12 Curriculum while overcoming their personal, social, and economic constraints in schooling.
This learning resource hopes to engage the learners in guided and independent learning activities at their own pace and time. Furthermore, this also aims to help learners acquire the needed 21st – century skills while taking into consideration their needs.
In addition to the material in the main text, you will also see this box in the body of the module:
Notes to the Teacher
This contains helpful tips or strategies that will help you in guiding the learners.
As a facilitator, you are expected to orient the learners on how to use this module. You also need to keep track of the learners’ progress while allowing them to manage their learning. Furthermore, you are expected to encourage and assist the learners as they do the tasks included in the module.
For the learner:
Welcome to Physical Science 11/12 Alternative Delivery Mode (ADM) Module on Wave Properties of Light.
Our hand is one of the most represented parts of the human body. It is often used to depict skill, action, and purpose. With our hands, we create, accomplish and learn. Hence, you are capable and empowered to successfully achieve the relevant competencies and skills at your own pace and time. Your academic success lies in your own hands!
This module was designed to provide you with fun and meaningful opportunities for guided and independent learning at your own pace and time. You will be able to process the contents of the learning resource while being an active learner.
This module has the following parts and corresponding icons:
What I Need to Know – This will give you an idea of the skills or competencies you are expected to learn in the module.
What I Know – This part includes activity that will check what you already know about the lesson. If you get all the correct answer (100%), you may decide to skip this module.
What’s In – This is a brief drill or review to help you link the current lesson with the previous one.
What’s New – In this portion, the new lesson will be introduced to you in various ways such as a story, a song, a poem, a problem opener, an activity, or a situation.
What is It – This section provides a brief discussion of the lesson. This aims to help you discover and understand new concepts and skills.
What’s More – This comprises activities for independent practice to solidify your understanding and skills of the topic. You may check the answers to the exercises using the Answer Key at the end of the module.
What I Have Learned – This includes questions or blank sentences/paragraphs to be filled in to process what you learned from the lesson.
What I Can Do – This section provides an activity that will help you transfer your new knowledge or skills into real-life situations.
Assessment – This is a task which aims to evaluate your level of mastery in achieving the learning competency.
Additional Activities – In this portion, another activity will be given to you to enrich your knowledge or skill of the lesson learned.
Answer Key – This contains answers to all activities in the module.
At the end of this module you will also find:
References – This is a list of all sources used in developing this module.
The following are some reminders in using this module:
- Use the module with care. Do not put unnecessary mark/s on any part of the module. Use a separate sheet of paper in answering the exercises.
- Don’t forget to answer What I Know before moving on to the other activities included in the module.
- Read the instruction carefully before doing each task.
- Observe honesty and integrity in doing the tasks and checking your answers.
- Finish the task at hand before proceeding to the next activity.
- Return this module to your teacher/facilitator once done.
If you encounter any difficulty in answering the tasks in this module, do not hesitate to consult your teacher or facilitator. Always bear in mind that you are not alone.
We hope that through this material, you will experience meaningful learning and gain a deep understanding of the relevant competencies. You can do it!
What I Need to Know
This module was designed to help you learn the wave properties of light. It is composed of activities that will make your learning process a more productive one.
CONTENT STANDARD: The learners demonstrate an understanding of light as a wave and as a particle.
PERFORMANCE STANDARD: The learners should be able to design and create a useful product for practical purposes that uses mirrors and lenses
LEARNING COMPETENCIES: Cite experimental evidence showing that electrons can behave like waves CODE: S11/12PS-IVg-64 Differentiate dispersion, scattering, interference, and diffraction CODE: S11/12PS-IVh-65
The module is divided into two lessons, namely:
- Lesson 1 – Wave Behavior of Electrons
- Lesson 2 – Wave Properties of Light
After going through this module, you are expected to:
- Identify the experimental evidence proving that electron behave as waves;
- Determine the significant explanations regarding the electron double-slit experiment; and
- Differentiate dispersion, scattering, interference, and diffraction.
What I Know
Multiple Choice
DIRECTIONS: Read each question carefully. Choose the letter of the best answer. Write your answer on a separate sheet of paper.
- Which of the following supports the wave nature of electrons?
A. Blue light is used in a double-slit experiment.
B. X-rays are used in crystallization.
C. Water is heated to 100ºC in a pot.
D. An electron enters a parallel plate capacitor which deflects the electrons downward.
- What is the importance of projecting electrons one at a time in the conduct of the double-slit experiment?
A. The detector needs time to reset to detect the next electron.
B. The slits are too narrow to allow two electrons to pass at the same time.
C. This prevented the electrons from interacting with each other.
D. Time is needed to generate more electrons.
- Which will not happen to electrons based on the double-slit experiment?
A. They sometimes behave like waves and particles.
B. They split in half and go through both slits simultaneously.
C. They behave like particles, but they are waves.
D. They are both waves and particles at the same time.
- Which is seen on the screen detector in the electron double-slit experiment?
A. white bands
B. dark bands
C. monochromatic light
D. alternating white and dark bands
- Which of the following observations in the double-slit experiment led to the conclusion that electrons behave like waves?
A. Electrons spread-out B. Electrons form diffraction patterns C. Electrons build up an interference pattern D. Electrons remain at specific locations and build up a distribution pattern
- It best describes how waves behave when they occupy the same location at the same time?
a. A crest overlapping with a crest will constructively interfere to produce a smaller wave b. A crest overlapping with a trough will constructively interfere to produce a smaller wave c. A trough overlapping with a trough will constructively interfere to produce a bigger wave. d. A trough overlapping with a trough will destructively interfere to produce a bigger wave.
[transcriber’s note: the options of item 5 begin at the top of this page; the stem of item 5 is on the previous page]
For questions 7-10, match the wave properties of light from Column A with the definitions given in Column B.
| A | B |
|---|---|
| 7 Dispersion | A. It refers to the bending of light around an obstacle |
| 8 Scattering | B. It is a combination of two or more waves. |
| 9 Interference | C. It is the splitting of white light into its component colors. |
| 10 Diffraction | D. The deflection of light by minute particles and molecules in all directions. |
- What color is bent the least during dispersion?
a. red b. blue c. orange d. violet
- What are the components of a white light?
a. red, blue, yellow b. magenta, cyan, yellow c. indigo, blue, violet d. ROYGBIV colors
- What will happen if the crest of one wave will interfere constructively with the crest of the second wave?
a. It will produce a large upward displacement.
b. It will produce a large downward displacement. c. The two waves will cancel out. d. Nothing will happen.
- Which of the following is an indicator of interference?
a. clear image b. dark bands c. monochromatic light d. alternating white and dark bands
- Which of the following best explains the scattering of light?
a. Light rays are scattered because they travel in a straight line. b. Light rays are dispersed because of diffuse reflection. c. Light rays are scattered because of dust particles and gas molecules in the atmosphere. d. Light rays are dispersed because there is an overlapping of waves.
Lesson 1: Wave Behavior of Electrons
What’s In
To help you fully understand the wave behavior of electrons, you must first understand the dual nature of light. Test your ability and apply the principles you have learned in the previous lesson by completing the sentences below. Choose your answer from the parentheses.
Light has a _____ (single, dual) nature. Sometimes, it behaves like a particle called _____ (proton, photon). Light’s particle-like traits are best explained by the _____ (photoelectric effect, scattering of light), the theory that _____ (Thomas Young, Albert Einstein) won his Nobel Prize for.
Light also behaves like a wave, which explains how it _____ (reflects, refracts) or how it bounces off in an obstacle. This results in the formation of an _____ (image, object) in a mirrored surface. Light, like any wave, is known to undergo _____ (reflection, refraction) when it passes from one medium to another medium with different optical densities. A light wave will bend _____ (towards, away) the normal when it passes from an optically denser to a less dense medium. On the other hand, if it is moving from a less dense to a denser medium, the wavefront will bend _____ (towards, away from) the normal.
Sir John Joseph Thompson and his son, George Thompson, shared one common thing, their scientific discoveries with electrons.
Sir Joseph John Thomson won a Nobel prize with his discovery of the electron, the first subatomic particle to be discovered. His son, George Thompson, won a Nobel prize for his discovery of the wave properties of an electron by diffraction.
Who is right, the father or the son?
What’s New
[photo: portrait of Sir Joseph John Thomson on the left and portrait of George Thompson on the right; speech bubbles read “Electron is a particle!” (from the left) and “Electron is a wave!” (from the right)]
https://upload.wikimedia.org/wikipedia/commons/thumb/c/c1/J.J_Thomson.jpg/461px-J.J_Thomson.jpg
Sir John Joseph Thompson and his son, George Thompson, shared one common thing, their scientific discoveries with electrons.
What is It
After learning that light could behave like a particle and a wave, it is understood that electron is both a particle and a wave at the same time. There are a lot of evidence to prove that electrons behave like particles. An electron is a type of subatomic particle which has a definite mass and definite charge and is often portrayed as a solid particle orbiting a nucleus of an atom.
But, what evidence supports the idea that electrons behave like waves? It is the double-slit experiment by Thomas Young. In this experiment, electrons are fired at a barrier with two narrow slits either simultaneously or one at a time. A detector screen was place to see the result. After passing through the narrow slits, an interference pattern was formed on the screen. Interference patterns are series of alternating bright and dark bands that are more of a characteristic of waves, rather than of particles.
What’s More
In this activity, you will use the double-slit experiment to investigate the nature of electrons by comparing it to classical objects and waves.
Part I.
Materials: paper cup, sand grains, cutter, bond paper, ruler.
Procedures:
- Make two narrow slits, 1.0 cm apart at the central bottom part of the paper cup.
[illustration: a circle with two narrow slits and a 1 cm scale, an arrow labeled “slits”, and an arrow leading to a paper cup]
Photo credits: Helen Grace L. Cabalag 2020
- Put a bond paper at the table. Hold the paper cup at the top of the bond paper. The bottom of the paper cup needs to be approximately 0.5 cm from the paper-covered tabletop.
- Pour sand through the paper cup and observe.
Guide Questions:
- Sketch your prediction of how the sand will pile up after it passed through the slits. Draw the profile of the sand and how it looked when viewed from the side. Show the slits in your diagram.
- Does the profile of the sand matched your prediction? Why does the sand form the observed shape?
- How do two grains of sand interact when they arrive in the same location at the same time?
Part II. The illustration below is a representation of the double-slit experiment conducted to electrons.
[chart: diagram; untitled. Labels as printed: “electron beam gun”, “Electrons”, “double-slit”, “screen”, “interference pattern”]
https://upload.wikimedia.org/wikipedia/commons/c/cd/Double-slit.svg2020
- Based on the figure, what is produced on the screen?
- Based on the previous lessons on the duality of a light wave, what does interference indicate?
- Imagine if the sand in Part 1 are electrons, how will these interact when they arrive in the same location at the same time?
- In an actual electron double-slit experiment, scientists assumed that electrons are bumping into each other (just like the sand grains) thus, creating the patterns on the screen. So, electrons are shoot one at a time to avoid collision of electrons. But the same results happened. Based on this, formulate a statement that describes an electron’s behavior.
Lesson 2: Wave Properties of Light
What’s New
Light is all around us. It allows us to see in the dark. Its properties are important in many aspects of our lives. Read the poem below and determine the wave properties.
WAVE PROPERTIES OF LIGHT
Helen Grace L. Cabalag, 2020
Light rays are separated
In the prism, they are refracted
White light becomes diffused.
ROYGBIV colors are produced.
Light rays spread in all directions
Deflected in its projections
Dust particles are the reasons.
That led to its path deviations.
When light rays combined,
They overlapped and twine
Constructive or destructive it will be
Bigger or smaller waves you will see.
When light rays are trying to pass
Through openings and gaps
Bending around the slits
Spreading more in narrow breaks.
What is It
The following are some of the wave properties of light.
Dispersion is the separation of white light into a spectrum of colors by the process of refraction. In this process, when white light passes from air into a glass prism, it splits into rainbow colors, ROYGBIV. Among these colors, violet bends the most, and red bends the least.
Scattering is the process where light rays deviate from its path due to non-uniformities in the medium through which they pass. These non-uniformities include dust particles, gas molecules, droplets, etc.
Interference is a phenomenon that occurs when two light waves meet while traveling along with the same medium. Superposition principle is the basic principle used in the interference of light. Incoming light waves can either superimpose
constructively or destructively. If they combine constructively, the intensity increases while when they add destructively, it decreases.
Types of Interference:
A. Constructive Interference – occurs at any location along with the medium where the two interfering waves have a displacement in the same direction. For example, the crest of one wave meets the crest of a second wave, they will interfere in such a manner as to produce a “super-crest.” Similarly, interference of a trough and a trough produces a “super-trough”. In this case, the intensity of the wave increases.
B. Destructive Interference – occurs when two interfering waves are with opposite displacements. For example, a crest meets with a trough. Destructive interference often decreases the resulting displacement of a wave.
Diffraction is a process in which a light ray travels through an obstacle or around a barrier and it spreads out as a result. For example, sending light rays through a slit will spread it out that makes a wider stream of light. The smaller the slit, the greater the diffraction effect. Diffraction also produces interference patterns.
What’s More
Ray diagrams are valuable tools in determining the movement of the incident and reflected rays taken by light. In this activity, determine the property of light illustrated in each diagram. Choose from the following
A. dispersion B. scattering C. interference D. diffraction
- [illustration: light source above a blue barrier with a narrow gap; red arcs spreading below the gap and overlapping]
light source
- [illustration: light source above a blue barrier with a gap; red arrows fanning out below the gap]
light source
- [illustration: a yellow light source with red arrows radiating in all directions]
light source
[transcriber’s note: a fourth diagram, a partly visible triangle outline, begins at the bottom of this page and continues beyond it; it is not transcribed here]
What I Have Learned
Complete the following sentences to summarize the important concepts discussed in this module.
- The wave behavior of electrons is supported using the _____ experiment.
- There are several wave properties of light namely: dispersion, scattering, _____ and diffraction.
- _____ is the splitting of white light into rainbow colors upon passing through a glass prism.
- _____ is the deflection of light by the dust particles and gas molecules.
- _____ is the superposition or the meeting of two waves. It can either be _____ or _____.
- _____ is the bending of light around an obstacle.
What I Can Do
THE WORLD OF COLORS
Materials: flashlight, red, green and blue lego blocks and cellophane
Procedures:
- Do the activity in a dark room.
- Turn on the flashlight. Point the rays to the three legos. Observe. What is the color of the light emitted by the flashlight? What is the color of the three lego blocks?
- Cover the flashlight with a red cellophane. Point the light rays to the three legos. Observe. Repeat this procedure using the green and blue cellophane.
- Consolidate the results in the data table below.
| Color of the Lego | Color of the light emitted by the flashlight: white | Color of the light emitted by the flashlight: red | Color of the light emitted by the flashlight: blue | Color of the light emitted by the flashlight: green |
|---|---|---|---|---|
| Red | ||||
| Blue | ||||
| green |
Critical Thinking Questions:
- What can you conclude from these observations? Explain in detail.
- What will be the color of the Lego if orange and violet light will be used?
- Choose one property of light that you learned and relate it to this dispersion activity. Explain briefly.
Assessment
Multiple Choice. Read each question carefully. Choose the letter of the best answer. Write your answer on a separate sheet of paper.
- Which of the following supports the wave nature of electrons?
- A. dispersion of white light in a prism
- B. double-slit experiment
- C. image formation in a mirror
- D. diffraction grating
- What scenario will result in the formation of interference patterns?
- A. Blue light is used in a double-slit experiment.
- B. X-rays are used in crystallization.
- C. Water is heated to 1000C in a pot.
- D. An electron enters a parallel plate capacitor which deflects the electrons downward.
- What is the reason in one at a time projection of electrons in the conduct of the double-slit experiment?
- A. The detector needs time to reset to detect the next electron.
- B. The slits are too narrow to allow two electrons to pass at the same time.
- C. This prevented the electrons from interacting with each other.
- D. Time is needed to generate more electrons.
- What is seen on the screen detector in the electron double-slit experiment?
- A. white bands
- B. dark bands
- C. monochromatic light
- D. alternating white and dark bands
- What observations in the double-slit experiment led to the conclusion that electrons behave like waves?
- A. Electrons spread-out.
- B. Electrons form diffraction patterns.
- C. Electrons build up an interference pattern.
- D. Electrons remain at specific locations.
- Which statement best describes how waves behave when they occupy the same location at the same time?
- A. A crest overlapping with a crest will constructively interfere to produce a smaller wave
- B. A crest overlapping with a trough will constructively interfere to produce a smaller wave
- C. A trough overlapping with a trough will constructively interfere to produce a bigger wave.
- D. A trough overlapping with a trough will destructively interfere to produce a bigger wave.
For nos. 7-10, refer to the following choices.
A. Dispersion B. Scattering C. Interference D. Diffraction
- It refers to the bending of light around an obstacle.
- It is a combination of two or more waves.
- It is the splitting of white light into its component colors.
- It is the deflection of light in all directions by minute particles and molecules.
- What color of light deviates greatly in the dispersion of white light by a prism?
- A. Violet B. Blue C. Green D. Red
- What property of light is responsible for the alternating light and dark bands when light passes through two or more narrow slits?
- A. Refraction B. polarization C. diffraction D. interference
- Which is responsible for the spreading of light as it passes through a narrow slit?
- A. refraction B. polarization C. diffraction D. interference
- What is the main principle used in interference?
- A. Heisenberg’s Uncertainty Principle
- B. Superposition Principle
- C. Quantum Mechanics
- D. Fermi Principle
- What will happen to the amplitude of the resulting wave if two waves of the same amplitude add constructively?
- A. It will double.
- B. It will decreases in half.
- C. It will become 4x.
- D. It will become one-fourth.
Additional Activities
ACTIVITY 1 – RAINBOW CD
Make your prism by lighting the back of a CD. Be patient with your experiment until you get the right angle. Draw what you have observed.
ACTIVITY 2 – “WAVES, LET’S MEET”
Directions: The sets of waves at the left represent two waves traveling at the same time. Predict what will happen to the waves upon superposition. Draw the corresponding wave output on the grid at the right. Identify if it is constructive or destructive interference.
- [illustration: two identical red wave curves on grids joined by “+”, with an arrow to an empty grid for the output] Photo credits: Helen Grace L. Cabalag 2020
- [illustration: two red wave curves on grids joined by “+”, with an arrow to an empty grid for the output] Photo credits: Helen Grace L. Cabalag 2020
QUESTION:
Which of the two sets of waves would produce a bigger wave? a smaller wave? Explain your answer.
Answer Key
[transcriber’s note: this page is printed upside down; the three boxes are transcribed below in their upright order, left to right as they appear once the page is turned]
What I Know
- A
- C
- B
- D
- C
- C
- C
- D
- B
- A
- A
- D
- A
- D
- C
What’s More
Lesson 1 Part I
[illustration: diagram of sand distribution across two slits, with a red curve; labels “sand distribution” above and “slits” below]
- Answers will vary.
- The sand piled up.
- They collide
Part II
- Alternating bright and dark bands
- Light is a wave
- They will collide
- Electron travels as waves.
Lesson 2
- C 2. D 3. B 4. A
Assessment
- B
- A
- C
- D
- C
- C
- D
- C
- A
- B
- A
- D
- C
- B
- A
References
http://www.perimeterinstitute.ca/images/perimeter_explorations/dark_matter/pi_quantum_booklet.pdf Accessed on July, 2020
http://www.sliderbase.com/spitem-101-1.html Accessed on July, 2020
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