Superposition of waves 

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Intros
Lessons
  1. Superposition of waves
  2. Introduction to superposition
  3. Interferences
  4. Standing waves
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Examples
Lessons
  1. Sketch the result of the following superposition cases on the dashes line. Identify the constructive and destructive interference and give the value of the resultant amplitude.
    Superposition of waves
    1. Bathtub water is sloshed back and forth with a frequency of 0.20Hz to produce standing waves. Suppose the standing wave produced is 120 cm long. Calculate the velocity of the water waves.
      Topic Notes
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      Introduction to Superposition of Waves

      Superposition of waves is a fundamental concept in wave physics that describes how multiple waves interact when they meet. This phenomenon occurs when two or more waves overlap in the same space, resulting in a combined wave that is the sum of the individual waves. Our introduction video provides a clear and engaging explanation of this concept, making it easier for students to grasp the principles of wave superposition. Understanding superposition is crucial in various fields of physics, including acoustics, optics, and quantum mechanics. It explains phenomena such as interference patterns, standing waves, and wave amplification. By mastering the concept of superposition, students can better comprehend complex wave behaviors and their applications in real-world scenarios. The video serves as an excellent starting point for exploring this essential topic, offering visual demonstrations and examples that bring the abstract concept to life.

      Superposition of Waves

      Superposition is a fundamental principle in wave physics that describes what happens when two or more waves meet or overlap in the same space. This concept is crucial for understanding various phenomena in nature and has applications in fields such as acoustics, optics, and quantum mechanics. At its core, superposition states that when multiple waves encounter each other, their individual displacements combine to form a resultant wave.

      When waves meet, they don't destroy or alter each other permanently. Instead, they interact momentarily, creating a combined effect before continuing on their original paths. This interaction can lead to interesting phenomena, depending on the properties of the interacting waves. The principle of superposition applies to all types of waves, including water waves, sound waves, light waves, and even matter waves in quantum physics.

      To understand superposition better, let's consider what happens when waves pass through each other. When two waves traveling in the same direction meet, their displacements add together. If the peaks of both waves align, they create a larger peak, resulting in constructive interference. Conversely, if a peak of one wave aligns with a trough of another, they may partially or completely cancel out, leading to destructive interference. This principle explains why we sometimes hear louder sounds when multiple sound sources combine or why we see bright and dark patterns in light interference experiments.

      Waves can also pass through each other in opposite directions. Imagine two pulses on a rope traveling towards each other. As they meet, their displacements combine momentarily. If both pulses are moving upward, they create a larger upward displacement at the point of intersection. If one is moving upward and the other downward, they may cancel out briefly. After passing through each other, both pulses continue their journey unaltered, maintaining their original shape and direction.

      During superposition, several wave properties come into play. The amplitude, which is the maximum displacement of a wave from its equilibrium position, is directly affected. When waves interfere constructively, the resulting amplitude can be greater than that of the individual waves. In cases of perfect destructive interference, the amplitudes may cancel out completely. However, it's important to note that the wave energy conservation of the waves is conserved during superposition.

      Wavelength, which is the distance between successive crests or troughs of a wave, remains unchanged during superposition. Each wave maintains its characteristic wavelength as it passes through other waves. Similarly, the speed of the waves is not altered by superposition. Waves continue to travel at their original speed, determined by the medium through which they propagate. This constancy of speed and wavelength leads to another important observation: the frequency of the waves also remains unchanged during superposition.

      To illustrate these concepts, consider the example of two water waves meeting in a pond. As the crests and troughs of these waves intersect, you might observe areas where the water level rises higher (constructive interference) and other areas where it remains relatively calm (destructive interference). Despite these momentary interactions, each wave continues its journey across the pond, maintaining its original properties.

      Another compelling example is the phenomenon of standing waves, which occur when two waves of the same frequency travel in opposite directions. This can be demonstrated with a rope fixed at one end. By shaking the free end at the right frequency, you can create a standing wave pattern where certain points (nodes) appear stationary while others (antinodes) oscillate with maximum amplitude. This is a result of continuous superposition between the incident and reflected waves.

      In acoustics, superposition explains how we can hear multiple instruments in an orchestra simultaneously. Each instrument produces sound waves that superpose in the air, reaching our ears as a complex but coherent musical experience. In optics, superposition is responsible for the colorful patterns seen in soap bubbles or oil slicks, where light waves reflected from the top and bottom surfaces interfere to produce vibrant colors.

      Understanding superposition is not just academically interesting; it has practical applications in various fields. In noise-canceling headphones, for instance, the principle is used to generate sound waves that are out of phase with ambient noise, effectively canceling it out through destructive interference. In fiber optic communications, superposition allows multiple signals to be transmitted simultaneously over the same fiber, greatly increasing data capacity.

      In conclusion, superposition is a powerful concept that explains how waves interact without permanently affecting each other. It demonstrates the additive nature of wave energy conservation.

      Interference of Waves

      Interference is a fascinating phenomenon that occurs when two or more waves overlap in space, resulting in a new wave pattern. This process is a direct consequence of the principle of superposition, which states that when multiple waves meet, their amplitudes combine algebraically at each point in space and time. Understanding interference is crucial in various fields, from physics and engineering to everyday applications.

      At its core, interference can be classified into two main types: constructive interference and destructive interference. Constructive interference occurs when the crests of one wave align with the crests of another wave, or when troughs align with troughs. This alignment results in an amplification of the wave amplitude. In contrast, destructive interference happens when the crests of one wave align with the troughs of another, leading to a reduction or even cancellation of the wave amplitude.

      To visualize these concepts, imagine two identical waves traveling towards each other. When they meet, the points where constructive interference occurs are called antinodes. These are locations of maximum displacement, where the waves reinforce each other. On the other hand, nodes are points where destructive interference takes place, resulting in zero displacement. In a standing wave pattern, antinodes and nodes remain stationary over time.

      The study of interference patterns often involves diagrams that illustrate these concepts. A common representation shows two waves approaching each other, with their crests and troughs clearly marked. As they overlap, the resulting wave pattern demonstrates areas of increased amplitude (antinodes) and areas of decreased or zero amplitude (nodes). These diagrams are invaluable tools for understanding and predicting interference effects in various scenarios.

      Interference manifests in numerous real-world scenarios, often with profound implications. In acoustics, interference plays a crucial role in the design of concert halls and auditoriums. Architects and sound engineers carefully consider how sound waves will interact within a space to ensure optimal listening experiences. Similarly, noise-canceling headphones leverage destructive interference to eliminate unwanted ambient sounds, creating a more immersive audio environment for the user.

      In the realm of optics, interference is the basis for many fascinating phenomena and practical applications. The iridescent colors seen on soap bubbles or oil slicks are a result of thin-film interference, where light waves reflected from the top and bottom surfaces of a thin film interfere with each other. This principle is also utilized in the production of anti-reflective coatings for eyeglasses and camera lenses, enhancing their optical properties.

      Interferometry, a measurement technique based on interference, has revolutionized various scientific fields. In astronomy, interferometers allow for incredibly precise measurements of celestial objects and phenomena. The recent detection of gravitational waves, a milestone in physics, was made possible through the use of laser interferometers capable of detecting minuscule distortions in space-time.

      The telecommunications industry heavily relies on interference principles to optimize signal transmission and reception. In wireless communications, techniques like beamforming use constructive interference to focus signal energy in specific directions, improving coverage and reducing interference with other signals. Conversely, managing destructive interference is crucial in preventing signal degradation in densely populated areas with multiple wireless devices.

      Even in everyday life, we encounter interference effects. The shimmering patterns seen when sunlight reflects off a CD or DVD are due to interference of light waves. The Moiré patterns observed when two similar patterns overlap, such as when looking through two window screens, are another visible manifestation of interference.

      Understanding and harnessing interference has led to numerous technological advancements. In the field of nanotechnology, researchers use interference patterns created by laser light to fabricate extremely small structures with high precision. This technique, known as interference lithography, enables the production of components for advanced electronic and photonic devices.

      As our understanding of wave behavior and interference continues to grow, so too does our ability to manipulate and utilize these phenomena. From enhancing communication technologies to pushing the boundaries of scientific measurement, interference remains a fundamental concept with far-reaching implications across various disciplines. By grasping the principles of constructive and destructive interference, along with the concepts of nodes and antinodes, we gain valuable insights into the complex and beautiful ways in which waves interact in our universe.

      Standing Waves

      Standing waves are a fascinating phenomenon in physics that play a crucial role in various applications, particularly in the realm of musical instruments. These unique wave patterns occur when two waves of equal amplitude and frequency travel in opposite directions, creating a stationary wave that appears to "stand" in place. To understand this concept better, let's explore how standing waves are produced, using the example of a guitar string as demonstrated in the video.

      When a guitar string is plucked, it vibrates back and forth, creating waves that travel along its length. These waves reflect off the fixed ends of the string, where it's attached to the guitar's body and the bridge. As the waves bounce back and forth, they interfere with each other, creating a pattern of nodes (points of no movement) and antinodes (points of maximum movement). This interference pattern results in a standing wave.

      For standing waves to occur, specific conditions must be met. First and foremost, the medium in which the waves travel must have fixed ends. In the case of a guitar string, these fixed ends are where the string is secured at both ends. This constraint is crucial because it determines the possible wavelengths that can form standing waves on the string. Secondly, the frequency of the waves must be precisely tuned to match the natural frequencies of the medium. These natural frequencies, also known as harmonics, are determined by the length, tension, and mass of the string.

      The relationship between frequency, wavelength, and the length of the string is fundamental to understanding standing waves. For a guitar string, the fundamental frequency (first harmonic) occurs when the wavelength is twice the length of the string. This creates a standing wave with nodes at both ends and an antinode in the middle. Higher harmonics are produced at integer multiples of this fundamental frequency, resulting in more complex standing wave patterns with additional nodes and antinodes along the string.

      Standing waves are not limited to guitar strings; they are essential to the functioning of all stringed instruments, as well as wind instruments like flutes and organs. In these instruments, standing waves are created within the body of the instrument, whether it's a string, a column of air, or a resonating chamber. The specific dimensions and properties of the instrument determine which frequencies will produce standing waves, thus defining the instrument's range and tonal qualities.

      Beyond musical applications, standing waves have significant importance in various fields of science and engineering. In acoustics, standing waves can affect the sound quality in rooms, leading to the design of concert halls and recording studios that minimize unwanted resonances. In electromagnetic theory, standing waves are crucial for the operation of antennas and waveguides. Even in quantum mechanics, the concept of standing waves is fundamental to understanding electron orbitals in atoms.

      The study of standing waves also extends to more practical applications. For instance, microwave ovens utilize standing waves to heat food efficiently. The wavelength of the microwaves is carefully calculated to create standing waves within the oven cavity, ensuring that the energy is distributed evenly throughout the food. In fiber optic communications, understanding and controlling standing waves is essential for optimizing signal transmission over long distances.

      To visualize standing waves, one can imagine a jump rope held at both ends by two people. When one person moves their end up and down at the right frequency, a standing wave pattern forms on the rope. This simple demonstration illustrates how energy can be transferred through a medium without the medium itself moving from its position a key characteristic of standing waves.

      In conclusion, standing waves are a fundamental concept in physics with wide-ranging applications. From the melodious tones of a guitar to the intricate workings of quantum mechanics, these stationary wave patterns demonstrate the beautiful interplay between frequency, wavelength, and the physical properties of a medium. By understanding the conditions necessary for standing waves to occur fixed ends and specific frequencies we gain insight into the harmonious world of vibrations that surrounds us, enriching our appreciation of music, science, and the natural world.

      Applications of Wave Superposition

      Wave superposition and interference are fundamental principles in physics that have numerous real-world applications across various fields. These phenomena occur when two or more waves combine, resulting in a new wave pattern. Understanding and harnessing these principles has led to significant advancements in acoustics, optics, and electronics.

      In acoustics, wave superposition plays a crucial role in noise cancellation technology. This application utilizes the principle of destructive interference, where sound waves with opposite phases are combined to cancel each other out. Active noise-canceling headphones employ this technique by generating sound waves that are the exact opposite of ambient noise, effectively reducing unwanted background sounds. This technology has revolutionized the audio industry, providing users with immersive listening experiences in noisy environments.

      Another acoustic application of wave superposition is in the design of concert halls and auditoriums. Architects and acoustic engineers carefully consider the reflection and interference of sound waves to create spaces with optimal sound quality. By strategically placing reflective surfaces and absorptive materials, they can enhance desired frequencies and minimize unwanted echoes, resulting in superior acoustic environments for performances and presentations.

      In the field of optics, wave superposition is fundamental to holography. Holograms are three-dimensional images created by recording and reconstructing light wave patterns. The process involves splitting a laser beam into two parts: one illuminates the object, while the other serves as a reference. When these waves interfere, they create a complex pattern that, when illuminated properly, reproduces a 3D image of the original object. Holography has applications in security, art, and medical imaging, among others.

      Interferometry is another optical application that relies on wave superposition. This technique is used in various scientific instruments to make highly accurate measurements. For instance, the Michelson interferometer, which splits a light beam and recombines it after traveling different paths, can detect minute changes in distance or refractive index. This principle is employed in gravitational wave detectors, precision distance measurements, and even in the manufacturing of computer chips.

      In the realm of electronics and telecommunications, wave superposition is essential for signal processing and transmission. In wireless communication, multiple signals are often transmitted simultaneously on different frequencies. The principle of superposition allows these signals to coexist without interfering with each other, enabling efficient use of the electromagnetic spectrum. Additionally, in fiber optic communications, wave division multiplexing (WDM) utilizes superposition to transmit multiple signals of different wavelengths through a single optical fiber, dramatically increasing data transmission capacity.

      The concept of superposition is also crucial in the development of quantum computing. Quantum bits, or qubits, can exist in a superposition of states, allowing quantum computers to perform certain calculations exponentially faster than classical computers. This property is at the heart of quantum algorithms that could revolutionize fields such as cryptography and drug discovery.

      Understanding wave superposition has led to advancements in medical imaging as well. Techniques like magnetic resonance imaging (MRI) rely on the superposition of radio waves and magnetic fields to create detailed images of the human body. Similarly, ultrasound imaging uses the interference patterns of high-frequency sound waves to visualize internal structures, providing a non-invasive diagnostic tool.

      In conclusion, the applications of wave superposition and interference are vast and diverse, spanning multiple disciplines and industries. From enhancing our audio experiences and creating stunning visual effects to enabling faster data transmission and advancing medical diagnostics, these principles continue to drive innovation and technological progress. As our understanding of wave behavior deepens, we can expect even more groundbreaking applications to emerge, further transforming our world and pushing the boundaries of what's possible in science and technology.

      Mathematical Description of Superposition

      The principle of superposition is a fundamental concept in wave physics that describes how waves interact when they meet. Mathematically, this principle states that when two or more waves overlap, the resultant displacement at any point is the algebraic sum of the displacements of the individual waves. This powerful concept allows us to analyze complex wave phenomena by breaking them down into simpler components.

      To express this mathematically, let's consider two waves, y(x,t) and y(x,t), where x represents position and t represents time. The superposition of these waves can be written as:

      y(x,t) = y(x,t) + y(x,t)

      This equation forms the basis of wave addition. For simple harmonic waves, we can express each wave in the form:

      y(x,t) = A sin(kx - ωt + φ)

      Where A is the amplitude, k is the wave number (2π/wavelength), ω is the angular frequency, and φ is the phase constant. When we superpose two such waves, we get:

      y(x,t) = A sin(kx - ωt + φ) + A sin(kx - ωt + φ)

      Calculating the resultant wave amplitude becomes more complex when the waves have different frequencies or wavelengths. However, for waves with the same frequency and wavelength, we can use trigonometric identities to simplify the expression.

      Consider two waves with the same frequency and wavelength but different amplitudes and phases:

      y(x,t) = A sin(kx - ωt + φ)

      y(x,t) = A sin(kx - ωt + φ)

      The superposition of these waves results in:

      y(x,t) = A sin(kx - ωt + φ) + A sin(kx - ωt + φ)

      Using trigonometric identities, this can be simplified to:

      y(x,t) = R sin(kx - ωt + φ)

      Where R is the resultant amplitude and φ is the resultant phase. The resultant amplitude R can be calculated using:

      R = (A² + A² + 2AA cos(φ - φ))

      And the resultant phase φ is given by:

      tan φ = (A sin φ + A sin φ) / (A cos φ + A cos φ)

      To illustrate these concepts, let's consider a simple example. Suppose we have two waves with amplitudes A = 3 and A = 4, and phase differences φ = 0 and φ = π/4. The resultant amplitude would be:

      R = (3² + 4² + 2·3·4·cos(π/4)) 6.46

      This mathematical treatment of wave superposition provides a powerful tool for analyzing complex wave phenomena. It allows us to predict the behavior of waves in various scenarios, from water waves in a pond to electromagnetic waves in communication systems. Understanding these principles is crucial in fields such as acoustics, optics, and quantum mechanics, where wave behavior plays a central role.

      In practice, the superposition principle can be applied to more complex situations involving multiple waves or continuous wave sources. For instance, in Fourier analysis, we decompose complex waveforms into sums of simple harmonic waves. This technique is widely use

      Conclusion

      In summary, we've explored the fascinating world of wave superposition, interference, and standing waves. These key concepts are fundamental to understanding how wave behavior in media interact and combine in various media. The introduction video provided a visual representation of these phenomena, making complex ideas more accessible. Superposition occurs when waves overlap, resulting in constructive or destructive interference. This principle leads to the formation of standing waves, where specific points remain stationary while others oscillate. These concepts have wide-ranging applications in physics, engineering, and everyday life. We encourage readers to delve deeper into this subject by exploring further applications and conducting experiments related to wave behavior in media. From musical instruments to noise-canceling headphones, the principles we've discussed play crucial roles in numerous technologies. By grasping these fundamental concepts, you'll gain a deeper appreciation for the intricate behavior of waves in our world.

      Superposition of Waves: Introduction to Superposition

      In this section, we will explore the concept of superposition of waves, understand the interference of waves, and introduce the idea of standing waves. The superposition principle is fundamental in wave theory and has significant applications in various fields of physics.

      Step 1: Understanding Superposition of Waves

      Superposition of waves occurs when two or more waves travel through the same medium simultaneously. During this process, the waves pass through each other without any change in their individual properties such as amplitude, wavelength, speed, or frequency. The key aspect of superposition is that the displacement at any point where the waves meet is the sum of the displacements of the individual waves at that point.

      Step 2: Displacement and Maximum Displacement

      When waves overlap, the resulting displacement is the sum of the displacements of the individual waves. This means that if two waves meet at a point, the total displacement at that point is the algebraic sum of the displacements of the individual waves. For example, if a yellow pulse is moving from left to right and a green pulse is moving from right to left, when they meet, the displacement at the point of overlap will be the sum of the displacements of the yellow and green pulses.

      Step 3: Example of Superposition

      Consider a scenario where a yellow pulse is moving from left to right and a green pulse is moving from right to left. When these two pulses meet, they will overlap, and the resulting displacement will be the maximum displacement, which is the sum of the individual displacements of the yellow and green pulses. After the overlap, the yellow pulse will continue moving to the right, and the green pulse will continue moving to the left, with no change in their individual properties.

      Step 4: Properties of Superposition

      One of the key properties of superposition is that the waves pass through each other unaffected. This means that after the process of overlapping, the individual waves continue their motion in their respective directions without any change in amplitude, direction, speed, or wavelength. This property is crucial in understanding how waves interact with each other in various physical scenarios.

      Step 5: Opposite Displacements

      When two waves with opposite displacements meet, the result is different. For instance, if a yellow pulse with positive displacement meets a green pulse with negative displacement, the displacements will cancel each other out, resulting in no motion at the point of overlap. This is an example of destructive interference, where the positive and negative displacements negate each other.

      Step 6: Continuation After Overlap

      After the overlap, the individual waves continue their motion in their respective directions. The green pulse continues to move to the left, and the yellow pulse continues to move to the right. The properties of the individual waves remain unchanged, demonstrating the principle that waves pass through each other unaffected by the process of superposition.

      Conclusion

      The superposition of waves is a fundamental concept in wave theory, illustrating how waves interact with each other when they travel through the same medium. Understanding this principle is essential for studying wave phenomena such as interference and standing waves. By examining examples of superposition, we can see how the displacements of individual waves combine to produce various effects, including maximum displacement and destructive interference.

      FAQs

      Here are some frequently asked questions about the superposition of waves:

      1. What is the principle of superposition in wave physics?

        The principle of superposition states that when two or more waves overlap in space, the resulting displacement at any point is the algebraic sum of the individual wave displacements. This means waves can combine without permanently affecting each other, leading to phenomena like constructive and destructive interference.

      2. How do standing waves form?

        Standing waves form when two waves of equal amplitude and frequency travel in opposite directions in the same medium. This often occurs in systems with fixed boundaries, like guitar strings or organ pipes. The interference between these waves creates stationary points called nodes (no movement) and antinodes (maximum movement).

      3. What's the difference between constructive and destructive interference?

        Constructive interference occurs when the peaks of two waves align, resulting in a larger amplitude. Destructive interference happens when a peak of one wave aligns with a trough of another, leading to a reduction in amplitude. These phenomena are key to understanding wave superposition effects.

      4. How is wave superposition applied in real-world technologies?

        Wave superposition has numerous applications, including noise-canceling headphones (using destructive interference), holography (creating 3D images through light wave interference), and fiber optic communications (transmitting multiple signals simultaneously). It's also crucial in musical instruments, where standing waves produce specific tones.

      5. Can wave superposition occur with different types of waves?

        Yes, superposition applies to all types of waves, including mechanical waves (like sound and water waves) and electromagnetic waves (like light). The principle remains the same regardless of the wave type, making it a universal concept in wave physics with applications across various scientific and engineering fields.

      Prerequisite Topics

      Understanding the superposition of waves is a crucial concept in physics, but to fully grasp its intricacies, it's essential to have a solid foundation in several prerequisite topics. These fundamental concepts not only provide the necessary background knowledge but also enhance your ability to analyze and interpret wave behavior in various contexts.

      One of the key prerequisites for understanding wave superposition is conservation of energy. This principle is vital when considering wave energy conservation during superposition. As waves combine, the total energy of the system remains constant, which is crucial for predicting the behavior of superposed waves. Understanding how energy is distributed and conserved in wave systems allows students to better comprehend the outcomes of wave interference and superposition.

      Another important prerequisite is the concept of simple harmonic motion. This fundamental type of oscillation is closely related to wave motion and provides a foundation for understanding the periodic nature of waves. By mastering simple harmonic motion, students can more easily visualize and mathematically describe the behavior of individual waves, which is essential when studying their superposition.

      Additionally, a strong grasp of trigonometric identities and their integration is crucial for analyzing wave superposition. Waves are often described using trigonometric functions, and when multiple waves combine, these functions need to be added and manipulated. Proficiency in working with trigonometric identities allows students to simplify complex wave equations and solve problems involving superposition more effectively.

      The interplay between these prerequisite topics creates a comprehensive framework for understanding wave superposition. For instance, the conservation of energy principle helps explain why the amplitude of superposed waves can sometimes exceed that of individual waves, while knowledge of simple harmonic motion aids in predicting the resulting wave patterns. Similarly, trigonometric skills are indispensable when mathematically expressing and analyzing the combination of multiple wave functions.

      By thoroughly understanding these prerequisite topics, students can approach the study of wave superposition with confidence. They will be better equipped to visualize wave interactions, perform necessary calculations, and interpret the results of wave superposition in various physical scenarios. This foundational knowledge not only facilitates learning about wave superposition but also prepares students for more advanced topics in wave physics and related fields.

      In conclusion, mastering these prerequisite topics is not just about fulfilling academic requirements; it's about building a robust conceptual framework that enables a deeper, more intuitive understanding of wave superposition and its applications in the real world. As students progress in their studies, they'll find that this strong foundation continually supports their learning and problem-solving abilities in more complex wave-related phenomena.

      In this lesson, we will learn:

      • Waves superposition
      • Waves interference
      • Standing waves

      Notes:

      Superposition (When two or more waves travelling though one another)

      • As waves pass through each there is no change in:
        Amplitude, direction, speed, frequency, wavelength
      • The displacement at the point where they meet is the sum of the displacements.
      • When pulses pass through one another superposition takes place.

      Interference

      • When pulse meet at a point at the same time interference occurs.
      • Interference is the result of the superposition of two or more waves (the point where they meet).
      • Constructive interference: waves displacement are in the same direction, displacements add up, maximum displacement (ANTINODE)

      Superposition of waves

      • Destructive interference: waves displacement are in the opposite direction, displacements cancel out, zero displacement (NODES)

      Superposition of waves

      Standing waves
      • When a string is plugged pulses travel back and forth, reflecting from the ends producing a complex of superposition called standing waves. Superimposed waves can produce standing waves.

      Superposition of waves