Wavelength Definition and 1000 Threads

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. J

    DeBroglie wavelength, kE to (p) conversion?

    I have a relatively simple question. I should know this, but... I need to solve for the deBroglie wavelength when only the kinetic energy is known. Shouldn't I be able to convert kE to momentum (p), when the object does not have a known velocity or mass...? Much thanks... JD
  2. A

    DeBroglie wavelength and nucleon velocity

    Homework Statement Atomic nucleus consists of nucleons. What velocity (order of magnitude estimate) will a nucleon have inside a nucleus? Homework Equations \lambda = h/mv v = h/m\lambda The Attempt at a Solution The wavelength of a nucleus is on the order of 10^-15/m...
  3. M

    Wavelength - Yellow line in the spectrum of a sodium lamp

    Homework Statement The outermost electron in a sodium atom can be in these energy states: (1)-0.82 aJ, (2) -0,48 aJ, (3) -0.31 aJ 1 aJ= 10^{-18} J. When we study the spectrum of a sodium lamp, we see a yellow line. Use the above given energy states to determine the wavelength of this yellow...
  4. M

    Determination of the wavelength of a spectral line

    Homework Statement With a spectrometer we can see a black line in the spectrum of the sun at the angle \theta =20,73 from the maxima of 0. order. The line is in the maxima of the second order. Use the interference formula (given under heading 2) to determine the wavelength and color this...
  5. N

    If light is a particle, what is wavelength / frequency ?

    If light is a particle, what is "wavelength"/"frequency"? Hello, Is the wavelength of a particle simply the wavelength of the psi-function before measurement? Or (/and?) is it an intrinsic property that is "even there in the particle" when you measure the presence of the particle (i.e...
  6. T

    Transparency of the sun to extremely long wavelength photons

    Hi, new here. This came up briefly elsewhere and we didn't have the cerebral fire power to get very far with it. Consider very, very long wavelength photons, (or conversely, very very low energy photons) produced inside the sun. Wavelengths we are looking at are in the range of 1 light...
  7. E

    Contracting Wavelength via mirrors.

    Suppose we had two perfectly parallel and reflecting mirrors located 10000 meters apart in a vacuum. A radio wave with wavelength 3 meters is emitted at the center first mirror in the direction of the center second mirror for exactly 10 nanoseconds (the overall length of the wave would be 3...
  8. S

    Mechanical Oscillator: finding frequency and wavelength of transverse wave

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  9. D

    How Can I Determine Energy and Dimensions of a Signal with Perfect Antennas?

    Dear all, Let's assume that I have just bought the perfect omnidirectional antenna and I try to understand how the wavelengths are transmitted. If I got it right, there are wavelengths getting 'out' towards the 360 degrees directions. Now let's assume that I have a perfect receiver antenna...
  10. Saitama

    Answer: Find Wavelength of H-atom Induced Radiation

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  11. N

    Diffraction - Why must slit width be comparable to the wavelength of light?

    Hey guys, In diffraction of light, why must the slit width be of comparable size to the wavelength of the light being shone on it for diffraction to be noticed most? Thanks
  12. Saitama

    Finding Wavelength of Incident Radiation on H-Atom

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  13. E

    What Wavelength of Light Dislodges an Electron from Sodium?

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  14. e2m2a

    De Broglie wavelength shift in gravitational fields

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  15. C

    Calculating wavelength of a standing wave on a guitar string

    Not sure how to figure this one out, or where to start: The diagram represents a snapshot of a standing transverse wave on a flexible guitar string taken when the displacement is at a maximum. (Note: the vertical scale is very exaggerated, the actual sideways displacement of the string is...
  16. K

    Finding wavelength of an electron

    Homework Statement What is the wavelength of an electron with a kinetic energy of 2.00 MeV? What is the wavelength of an electron with a kinetic energy of 2.08 GeV? (Possibly useful constants: hc = 1239.8 eVnm, rest energy of the electron: E0,e = 511.0 keV.) Homework Equations...
  17. E

    Why Does Redshift Occur?; Other Factors That Cause Elongation Of Wavelength?

    Me and my Dad were having a conversation about the elongation of EMR wavelengths over an extended period of time. He began to explain to me what Red Shift was but I couldn't understand what he was trying to get at (he's a poor explainer, or I'm bad listener). But his explanation did spark an...
  18. B

    Understanding the Compton Effect: Explaining Wavelength Change

    Can somebody please explain the Compton effect to me... I don't get how Compton came up with the wavelength after scattering - the initial wavelength = h/the mass of the electron*the speed of light*(1-cosine of the scattering angle). Thank you!
  19. jaketodd

    Exploring the Mystery of the De Broglie Wavelength

    Why is the de Broglie wavelength sometimes larger than the particle it describes? Thanks, Jake
  20. A

    Waves question (wavelength, period, etc)

    Homework Statement A transmitter sends out 1.8x10^7 waves per minute and generates a standing wave pattern. The radio waves travel at the speed of light to a receiver 20.0km away. Determine : a) the frequency in herts b) period c)wave length d) the time for one crest to travel from the...
  21. B

    What happens when a photon meets a virtual photon of the same wavelength?

    As I understand it, photons are their own anti-particle, and at all points in space there are a lot of virtual particle-antiparticle pairs being created and annhilated (perhaps infinite?), so it would seem to me that on it's journey from point A to point B that there is at least some likeliehood...
  22. F

    Calculating Wavelength and Understanding Sound Interference in a Room

    Homework Statement two speakers which are placed 5m apart at one end of a large room are connected to a signal generator which puts out a 2kHz sinusoidal waveform. Calculate the wavelength of the sound. The second part of this question is: describe what a person would hear as he moves slowly...
  23. C

    Astrophysics - Temperature of a star via flux and wavelength

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  24. B

    Frequency Shifts: Doppler Effect & Wavelength

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  25. A

    Blackbodies and Maxwell's Whole Number Wavelength Theory

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  26. A

    How Do You Calculate Wavelength in a Standing Wave Scenario?

    Homework Statement Sally sue and her partner hold a spring 4 meters apart. There were 5 nodes in the standing waves produced. Sally moved her hand from the rest position back and forth along the floor 20 times in 4 seconds. F Homework Equations The Attempt at a Solution Since...
  27. T

    Photon wavelength shift from gravitational lensing?

    The basic question is: will a photon traveling through a vacuum lose some of its energy due to interactions with gravity from a massive body? Gravitational lensing implies that the photon will change its initial direction but is its energy conserved (i.e. differences in blueshift/redshift...
  28. A

    Calculating Wave Properties: Frequency, Wavelength, and Speed

    Homework Statement the displacement of a wave traveling in the negative x-direction is given by y(x,t)=(5.2cm)cos(5.5x/m+72t/s) where x is in metres, t is in seconds, calculate: i)the frequency ii) the wavelength iii) the speed of this wave) The Attempt at a Solution i have...
  29. B

    Compton Wavelength, h and h bar

    I have found 2 different representations of Compton wavelength: \lambda= \frac{h}{mc} and \frac{\bar{h}}{mc} which of these is correct, and if both are right, how do you know when to use one or the other? (note: the second equation contains a h bar as in " h bar = h/2pi ")
  30. P

    Extreme Ultraviolet Wavelength Question

    On the Solar and Heliospheric Observatory (SOHO), a satellite which observes the sun from the First Lagrangian Point, there are 4 different Extreme Ultraviolet Imaging Telescopes, each with a different wavelength: 171 Angstrom - 1 million degrees Kelvin 195 Angstrom ~1.5 million degrees...
  31. W

    De Broglie wavelength neutrons

    Question-A certain crystal has a set of planes spaced 0.376 nm apart. A beam of neutrons strikes the crystal at normal incidence and the first maximum of the diffraction pattern occurs at a scattering angle (i.e angle between incoming neutrons and reflected beam) of 41.4 degrees. What is the de...
  32. S

    Why is any wave defined by the wavelength, but not by the amplitude?

    Any wave is identified by its wavelength (or frequency), and the wavelength is the distance between the two consecutive crests (or troughs) in wave trains. But wave is not identified by its amplitude. The wave could have been described by the amplitude as it doesn't require two wave trains (or...
  33. G

    What Is the De Broglie Wavelength?

    i was working on atomic structure and i stuck here. how can a wave be associated to any material? is it related to wavelength of colur it emits or is it the wavelength of vibrations after it has been stuck by something? what is it??
  34. S

    Calculate DeBroglie Wavelength & Kinetic Energy of Electron

    Homework Statement What is the DeBroglie wavelength of an electron whose energy is (a) 1.0eV (b) 100eV? What is the kinetic energy in eV of an electron whose DeBroglie wavelength is that of visible red light at 650nm? Homework Equations λ=h/p = h/mv h = Planck's constant...
  35. I

    Is amplitude always perpendicular to the rest axis?in a wavelength

    Is amplitude always perpendicular to the rest axis? in a wavelength amplitude it the distance between either the crest or through from the equbilium line. then in the case of transverse vibration, what is its amplitude? thanks
  36. J

    Understanding cut off wavelength at edge of Bremsstrahlung region

    Hello, I am trying to understand an equation stated in the book 'Principles of Protein X-Ray Crystallography' by Jan Drenth (The exact page I am reffering to can be found here...
  37. F

    Modern Physics Introduction Photon Energy and Wavelength

    Homework Statement Suppose that a beam of light consists of photons having an energy of 5.4 eV. what is the wavelength of the light? Homework Equations hc = 1240 eV*nm E = \frac{hc}{\lambda} The Attempt at a Solution 5.4eV = \frac{1240eV*nm}{\lambda} \lambda =...
  38. F

    Modern Physics Introduction Standing Wavelength and Frequency

    Homework Statement Find the length of the smallest standing wave that can be formed with light having a frequency of 600THZ. Homework Equations f = 600*10^{12}Hz c = 2.998x10^{8}\frac{m}{s} \lambda f=c The Attempt at a Solution \lambda f=c \lambda...
  39. O

    What is the wavelength of tsunami waves?

    Why tsunami waves have a very long wavelengths?
  40. G

    DeBroglie Wavelength: Solving for Electrons in Relativity

    Homework Statement An electron of charge e and rest mass m0 is accelerated to relativistic speeds by a potential V. Show that the deBroglie wavelength is given by the expression lambda= h(2m0eV)-1/2 (1+eV/2m0c2)-1/2 The Attempt at a Solution eV = gamma m0c2 equation one p = gamma...
  41. P

    Standing Wave Wavelengths on 12m Rope: 2m, 1m & 5.5m

    If two wavelengths of standing waves on a 12 meter rope secured at both ends are 2 meters and 1 meter, which of the following could not be a standing wave wavelength on teh same rope with the same tension? Choices are: 4m, 2.5m, 1.5m, 67cm 12-2 =10, so 1\2 would be 5 and 12-1 = 11, so...
  42. J

    What Is the Wavelength of a Laser Used in CD Data Retrieval?

    Homework Statement A CD stores data in digital form by encoding it into a grooves as a series of bumps of height 160 nm above the base of the groove. Explain how infromation is picked up from the CD using a laser and calculate its wavelength. Can someone please explain how to do this...
  43. S

    Can someone confirm my calculations please (wavelength & grating seperation)

    Good evening everyone I was hoping someone could confirm my calculations are correct.I will put the question in normal font and my calculations in red bold: A laser of wavelength 500nm and grating separation of 100μm: a) find the angle of the first order of fringe spacing b) Distance of the...
  44. C

    How Fast is an Electron with a De Broglie Wavelength of 1.6 Å?

    Homework Statement What is the velocity of an electron having a De Broglie wavelength that is approximately the length of a chemical bond? Assume this length to be 1.6 A Homework Equations wavelength= h/mv The Attempt at a Solution I fixed the equation to isolate the velocity...
  45. H

    How Do Wavelength and Frequency Relate in Different Mediums?

    i need help in these equations please : Q1 - if there is a frequency 440Hz for a sound wave in air with velocity 430 m/s calculate wavelength and wavenumber. --------------------- Q2- the speed of light about 3X 10⁸ m/s find the wave length and wave number for the frequency 5x 10¹⁴ Hz...
  46. U

    Spatial Wavelength of a Halbach array (Magnetism)

    Hello everybody Basically as the topic states: How can you calculate "The spatial wavelength of a Halbach array" (symbol lambda)? Context: The reason I ask is that since I've got bored during my easter holidays I decided to try a wee science project and try and make a model of an...
  47. M

    Determining wavelength of double slit experiment

    Homework Statement If i have the intensity pattern of a double slit experiment and aim to find the wavelength of the monochromatic light incident on the slits with the following information, - width of each slit - distance to the screen - intensity pattern (displacement Vs intensity)...
  48. C

    How does a prism affect wavelength?

    I know that prisms create dispersion and cause different frequencies of light to travel at different angles relative to the normal, and that the prism affects the wavelength and speed of the waves, but what exactly is the nature of this relationship? Other than spreading various frequencies out...
  49. B

    Can the intensity of soundwaves be affected by the size of a gap?

    Ok so I was sitting out back one day listening to some music with some friends around. We had some music playing on a stereo inside the house and we were out the back with the glass door open about 10 cm's. I thought I noticed that some sounds with different frequencies seemed louder then...
  50. V

    Question about filtering out the blue wavelength from lights

    I volunteered to help out with a research project, and we need a solution for a way to filter out light of the blue wavelength from a light source. THe blue wavelength is the only wavelength we want to remove. I was wondering if anyone here had any suggestions? Someone from the project suggested...
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