What is Wavelength: Definition and 1000 Discussions

In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The inverse of the wavelength is called the spatial frequency. Wavelength is commonly designated by the Greek letter lambda (λ).
The term wavelength is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids.Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths.Wavelength depends on the medium (for example, vacuum, air, or water) that a wave travels through. Examples of waves are sound waves, light, water waves and periodic electrical signals in a conductor. A sound wave is a variation in air pressure, while in light and other electromagnetic radiation the strength of the electric and the magnetic field vary. Water waves are variations in the height of a body of water. In a crystal lattice vibration, atomic positions vary.
The range of wavelengths or frequencies for wave phenomena is called a spectrum. The name originated with the visible light spectrum but now can be applied to the entire electromagnetic spectrum as well as to a sound spectrum or vibration spectrum.

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  1. P

    Compton Scattering- finding photon wavelength

    Homework Statement An electron moving to the left at 0.8c collides with an incoming photon moving to the right. After the collision, the electron is moving to the right at 0.6c and an outgoing photon moves to the left. What was the wavelength of the incoming photon? Homework Equations p=γmv...
  2. YMMMA

    Physics: transverse wave & wavelength & motion

    Homework Statement the question asks at which point is the string moving upward at the instant shown? Homework Equations No equations needed The Attempt at a Solution I am not sure how I should approach this type of questions. A) will move downward B) downward then upward C) upward then...
  3. YMMMA

    Physics: wavelength of sound waves

    Homework Statement Stated in the attached file. Homework Equations Wavelength = 2 times length divided by harmonic I don’t know if it’s the relevant equation The Attempt at a Solution I used the equation I wrote. So, if the left side is 10cm longer, I guess it might be 2(10).
  4. Helloworld

    Frequency and wavelength of a wave on a vertical rope

    Homework Statement A long, heavy rope hangs straight down from a high balcony on an apartment building. The lower end of the rope hangs about 1.0 m above the ground. If you grab onto the lower end and waggle it back and forth with constant frequency f, a wave travels up the rope. What would...
  5. B

    Resonant Lengths in open air column question

    Homework Statement An organ pipe 1.2m long and open at both ends produces a note with the fundamental frequency. If the speed of sound in air is 345 m/s, what is the fundamental frequency? Homework Equations Wave equation (f = v/lambda) The Attempt at a Solution My textbook solves the problem...
  6. S

    Angle of Incidence, Propagation Constant and Wavelength

    Homework Statement Light of free-space wavelength λ0 = 0.87 μm is guided by a thin planar film of thickness d = 3.0 μm and refractive index n1 = 1.6, surrounded by a medium of refractive index n2 = 1.4 critical angle = 61.04° n0 = 1.00 (a) Determine (i) the angle of incidence θ and (ii) the...
  7. M

    Two loudspeakers emit waves, find wavelength

    I solved it, but then saw another solution online and am wondering if is is correct (since it is much faster than mine) and if my reasoning of it is correct 1. Homework Statement Two loudspeakers emit sound waves along the x-axis. A listener in front of both speakers hears a maximum sound...
  8. N

    With the info given, what are 3 ways to calculate wavelength?

    Homework Statement In an investigation into single-slit diffraction, a laser is used to produce an interference pattern on a screen. With the following information determine the wavelength of the light in 3 different ways. · The angle to the third dark fringe is 2.6˚. · The...
  9. Amaterasu21

    I SR Light Wavelength & Direction: Questions Explained

    Hi all, I have two questions about light in Special Relativity. (I'm going to pad these questions out with a few statements about my understanding of length contraction and time dilation, so you can see how I currently think about it and clear up any misconceptions if I've got the basic idea...
  10. B

    A Nanotube diameter versus emitting wavelength

    Can somebody please help me I am looking for the diameter required of a carbon nanotube to emit a wavelength of 800 nm. If I could just find a graph of nanotube diameter versus emitting wavelength.
  11. enter

    I What is the highest frequency of electromagnetic radiation?

    Title says it all. Also, if the frequency of electromagnetic radiation is limited, why? My guess is the wavelength is limited to the Planck length, and when I plug those numbers into the calculator, I get 1.855 * 10^43 Hz. The maximum (Edit: observed) frequency of a gamma ray is 3 * 10^20 Hz...
  12. Krushnaraj Pandya

    Wavelength = deBroglie Wavelength?

    Homework Statement Find the retarding potential required to stop electron of de-broglie wavelength 0.5 nm Homework Equations 1)de-broglie wavelenght=h/momentum 2)eV=KE of electron 3)KE=p^2/2m The Attempt at a Solution Using the above three relations is giving me an incorrect answer for V...
  13. M

    Light wavelength transmission through ice

    I am studying hailstones. I have set up an experiment to pass colored light through hail, one color at a time for the colors of the visible spectrum, Red, Orange, Yellow, Green, Blue, Indigo and Violet (ROYGBIV). I have measured the dominate wavelength for each color with a photo spectrometer...
  14. P

    Finding the mass of a photon with given wavelength

    Hi, stuck on this question, hoping someone could help 1. Homework Statement Two identical photons of wavelength 4.22x16^-7m are created when a certain amount of matter M, is converted into energy, calculate the Mass (M) The Attempt at a Solution E= hf which is hc/wavelength E= 4.71x10^-19J...
  15. Sandeep T S

    I How the wavelength of a photon is measured experimentally?

    How wavelength of photon is measured experimentally?
  16. J

    De Broglie wavelength of electron and proton

    Homework Statement Homework EquationsThe Attempt at a Solution de Broglie wavelength λ of a particle = h /P a) since mass of proton is more than electron and speed is same , momentum of proton is more . De Broglie wavelength of proton will be less . b) wavelengths will be same . c) Using...
  17. B

    I Effect of impedance changes less than a wavelength

    I am interested to know what is the impact of various length scales of impedance changes on wave propagation. From undergraduate physics (a few years ago for me) I roughly remember how to derive reflection and transmission coefficients for a wave traveling from one medium to another with a...
  18. T

    Zeeman Effect: Splitting of Lyman-α Wavelength

    Homework Statement The Lyman-α line (n = 2 → n = 1) has a wavelength of 121.6nm in the absence of a magnetic field. When B = 1 Tesla, into how many wavelengths will this split and what are their wavelengths? (You may need the values μ B = 9.274 × 10 −24 J/T, h̄ = 1.054 × 10 −34 Js and c =...
  19. O

    Wavefunctions and the de Broglie wavelength

    The position wavefunction makes a spatial probability amplitude wave right? And it is the combination of different frequencies My question is that if these frequencies are the spatial frequencies in the debrogile relations
  20. Kenneth Boon Faker

    Why do cars crash? (Instead of passing through each other)

    If everything is made of atoms, and if atoms have so much empty space inside them - and if the building blocks of atoms are made up of wave-like particles that aren't solid (strictly speaking) - then why do cars crash and billiard balls bounce off each other, as opposed to passing through each...
  21. FredFlintstone

    Obtaining 700nm light wavelength

    If I had a white light bulb and covered it with the right colour of film (red-ish) will the resulting wavelength be about 700nm?
  22. C

    Finding a third method to determine light wavelength

    Homework Statement a) explain why a pattern of bright and dark fringes is visible on a screen when a light is shone through a double slit. b) Use this data to determine the wavelength of light being used to create the interference pattern. Do this three different ways. -The angle to the eighth...
  23. M

    Inteference Fringes of Double Slit Experiment in Water

    Homework Statement Suppose a double-slit experiment is immersed in water (with an index of refraction of 1.33). When in the water, what happens to the interference fringes? Homework Equations λ = λ0 / n y = (λmL) / d d = distance between slits L = distance to viewing screen n = index of...
  24. G

    Maximum Wavelength and Scattering Angle for Triangular Lattice

    Homework Statement A triangular lattice of lattice spacing ##a=2 ## angstroms is irradiated with x-rays at time zero of wavelength 20 angstroms at an incident angle of ##\alpha =135##. 1) What is the maximum wavelength of the incident x-rays? 2) What is the scattering angle ##\Omega## for...
  25. Sahar ali

    I The 6th Spectral Series: Wavelength & EM Spectrum

    we know the five spectral series of Lyman, Balmer, Paschen, bracket, and Pfund their wavelength and also the part of EM spectrum they fall in, my question is why do we neglect the 6th series in the spectrum? and in what part of EM spectrum the 6th series exist and what could be its wavelength...
  26. harambe

    What is the wavelength of a pulse on a hanging rope with changing tension?

    Homework Statement A uniform rope of length 12cm and mass 6kg hangs vertically from a rigid support.A block of mass 2kg is attached to the free end of the rope.A transverse pulse of wavelength 0.06m is produced at the lower end of the rope.What is the wavelength of the rope ,when it reaches...
  27. Buzz Bloom

    What fraction of long wavelength EM gets through a small hole?

    Assume a source of EM radiation at wave length λ hits a barrier with a small circular hole of diameter d << λ. What fraction of the radiated power (watts) that hits the hole passes through it? Does it depend on the thickness of the barrier? I understand that after passing through the hole, the...
  28. I

    What is the wavelength difference based on a mini spectrom.?

    Homework Statement I'm a bit stuck on how to approach this problem. A miniature spectrometer used for chemical analysis has a diffraction grating with 800 slits/mm set 25.0 mm in front of the detector "screen." The detector can barely distinguish two bright lines that are 30 μm apart in the...
  29. R

    Composition of Light: Questions & Answers

    Hi everyone, I have a few questions about the composition of light: First, what is it? Is white light the result of all color wavelengths present in an area? Second, if so, then why is there no interference in waves of light (or is there)? Third, if photons all travel at the same speed, then...
  30. Sritika

    I De-Broglie Wavelength of a captured electron?

    For a proton to capture an electron to form a neutron and a neutrino (assumed massless), the electron must have some minimum energy. For such an electron,how can the de-Broglie wavelength be found out?
  31. V

    Mathematica Color by Wavelength in Wolfram Mathematica: Easy Guide & Tips

    Hello, I'm wonder if is possible in Wolfram Mathematica to fill some object or just set a color of object by a entering a wavelength, i.e. I write 450 and the line will be blue etc. Please advise me, I didn't find anything useful. Thank you all.
  32. S

    I Energy-momentum formula and deBroglie wavelength

    Hi everyone, Im a little bit confused about deBroglies procedure on introducing his famous Matterwave formula. People already knew that the wavelength of the light was equal to Lambda = h/p. The term p comes from the energy-momentum formula; for the light the restmass = 0 so E =pc etc. As...
  33. S

    A What is the Wavelength of the Pilot Wave in the Pilot Wave Theory?

    Hi, I am new to the Pilot Wave theory. In my understanding this theory gives a hope for reconstruction of the realism. But I have several maybe naif questions. What is the wavelength of the pilot wave? Is it the same as deBroglie wavelength formula? Very often people use the walking droplets...
  34. A

    Optics: How would you determine wavelength?

    If there is an light source that is emitting light with the wl of 450nm (blue) and it illuminated a low reflective red object. How would the wavelength be different then if the object was a white object or the emitted light is from a white led. How would we determine this. I am working on a...
  35. Simon Peach

    B Exploring Echoes of Electromagnetic Wave Lengths

    In the electromagnetic wave lengths say from x-rays to the 21 cm hydrogen line, the wave has a wave length. When it hits a receiver, eye, camera sensor whatever, it is turned into an electrical signal that can be interpreted by that device. Now we get to my question, is there an echo of that...
  36. Pushoam

    De – Broglie wavelength of O_2

    Homework Statement Homework EquationsThe Attempt at a Solution [/B] De – Broglie wavelength of ## O_2 ## molecule is ## \lambda = \frac h p ## Assuming that the speed of molecule is small enough to take non – relativistic calculation, ## \frac {...
  37. Richie Smash

    Wavelength of Sound: Solve Using X & Y

    Homework Statement Hello, If one can see the image I posted, the question that follows is this: Use the information provided to obtain a value for the wavelength of sound emitted. The signal is at maximum intensity at X, and minimum at Y. http://uploads.im/7wJOq.jpg Homework Equations Now I...
  38. G

    I How energy of light is conserved when passing through medium

    The velocity of light changes when it passes through a medium of a different refractive index. So let's suppose the light is traveling through a vacuum at a velocity c and then passes through a glass wall. Its velocity decreases while traveling through it but then speeds back up to c after...
  39. Pushoam

    Wavelength of em radiation of H - atom

    Homework Statement Homework EquationsThe Attempt at a Solution E = (13.6 – 3.4 = 10.2)eV = ## \frac {hc } { \lambda } ## =1.22 * 10^{-5} cm So, the correct option is (a). Is this correct?
  40. A

    Can we vary the wavelength of an LED light

    I would like to start growing plants in an artificial simulated environment with very low cost, hence i would like to know whether if i could vary the wavelength of light using a normal led light by varying voltage or current
  41. N

    Find Wavelength Homework: Solve with Plank's Constant

    Homework Statement https://imgur.com/a/9UhMA Homework Equations Wavelength = planks constant/ mass*velocity The Attempt at a Solution (6.626*10^-34)/((9.11*10^-31)(.01*10^8)) = .728nm which is an option but they have .243nm as the answer and I don't know where I did it wrong or what I...
  42. W

    Calculating Index of Refraction with Wavelength

    Homework Statement A beam of white light goes from air into water at an incident angle of 75 deg. What is the critical angle that the violet (410 nm) parts of the light is refracted? Homework Equations n1sin(θ1)=n2sin(θ2) n=c/v c=λf The Attempt at a Solution So sure, I get that the answer is...
  43. M

    Wave interference - coherence and wavelength

    I know to produce an observable inteference pattern two waves must be coherent(same frequency/phase differnce). Do coherent waves therefore always have the same wavelength? Is it possible to have interference between two waves with the same frequency and different wavelengths, and if so what...
  44. M

    Frequency and wavelength of vertical string wave

    Homework Statement A long, heavy rope hangs straight down from a high balcony on an apartment building. The lower end of the rope hangs about 1.0 m above the ground. If you grab onto the lower end and waggle it back and forth with constant frequency f, a wave travels up the rope. What would...
  45. J

    B What is the relation between wavelength and orbital?

    I am in a chemistry class, and there was an in class example on how to do this type of problem, but then when I looked in the book, there wasn't an equation. the questions are related to what the wavelength will be when electrons are moving between orbitals.
  46. Y

    A What frequencies allow for the long wavelength limit in solid state physics?

    In the "Introduction to Solid State Physics" by C. Kittel, there is a long wavelength limit in chapter 4 -Phonons I. When Ka << 1 we can expand cos Ka ≡ 1 - ½ (Ka)2 the dispersion relation will become ω2 = (C/M) K2 a2 Does anyone know what frequencies can allow this long wavelength limit to hold?
  47. M

    How does the wavelength change the amount of refraction?

    Using a green laser instead of a red laser seems to change the way the ray changes during refraction. Why is that so?
  48. J

    B Understanding Wavelength Size in Electromagnetic Waves

    Hey everyone hope you're doing well. I've always been confused about one particular aspect of electromagnetic waves. I understand that each frequency has a corresponding wavelength that is inversely proportionate and that the wavelength is the distance between successive crests or troughs. But...
  49. L

    A Spectroscopic vs. single wavelength ellipsometry

    Hello, I know that spectroscopic ellipsometry (SE) is more accurate than single-wavelength ellipsometry (SWE), but I would like to know how to create a dispersion model using SWE instead of SE. SE sweeps over wavelength, measures reflectivity vs. wavelength, and gives a variety of optical...
  50. H

    How to find the wavelength of the sound of the tuning fork?

    Homework Statement 1) find the wavelength of the sound of the tuning fork (cm) 2) what's the vertical distance x from the top of the pipe to the antinode above the pipe (cm) 3) find the frequency of the tuning fork (Hz) Homework Equations velocity = wavelength . frequency for pipe closed at...
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