Wavelengths Definition and 231 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.

View More On Wikipedia.org
  1. V

    What Frequency is Needed for Ultrasonic Cleaning of 3.0 x 10^-2 cm Particles?

    Homework Statement Particles approximately 3.0 x 10^-2 cm in diameter are to be scrubbed loose from machine parts in an aqueous ultrasonic cleaning bath. Above what frequency should the bath be operated to produce wavelengths of this size and smaller? Homework Equations Fn = nv/(2L) v=...
  2. P

    What Are the Approximate Wavelengths of Different Colors?

    i want to know the approx wavelengths of the following colours blue green bluishgreen yellow orange violet red the wavelengths should be in amstrong unit and also in meter .
  3. WolfOfTheSteps

    Solving Homework Questions on He-Ne Lasers

    Is this forum ok for posting EE student questions? I guess I'll find out. :biggrin: Homework Statement How many photons per second does a low power (1 mW) He-Ne laser (\lambda=336nm) emit? At what He-Ne laser power do you expect quantum effects to become important? The Attempt at...
  4. WolfOfTheSteps

    He-Ne Laser Wavelengths & Quantum Effects

    Homework Statement How many photons per second does a low power (1 mW) He-Ne laser (\lambda=336nm) emit? At what He-Ne laser power do you expect quantum effects to become important? The Attempt at a Solution I got the answer to the first part, 1.7\times 10^{15} photons/second. But the...
  5. S

    Destructive interference in wavelengths question

    1. A nonreflective coating (n = 1.24) covers the glass (n = 1.52) of a camera lens. Assuming that the coating prevents reflection of yellow-green light (wavelength in vacuum = 564 nm), determine the minimum nonzero thickness that the coating can have. 2. wavelength of the light in the...
  6. Simfish

    Are wavelengths well defined or vague?

    As in, for example, boundaries between UV and visible, UV-A and UV-B, blue and purple, gamma rays and x-rays. Or are they ill-defined and subject to the Sorites Paradox? Also, does anyone know if there is a highest level of energy a gamma ray can have? Thanks!
  7. R

    What main wavelengths are within sunlight (p.s. not a hw problem)

    I ordered these giant fesnel lenses online. They are about 2.6 by 3.3 feet, and can supposedly melt asphalt. I was just wondering what is the main wavelength that causes the energy: visible light, ultra-violet, infrared, some other that I don't know about, or all of them?
  8. Y

    Do photons have finitely many wavelengths?

    Hi all, If the energy states of electrons are quantized, are there finitely many wavelengths that a photon can have within, say, the visible spectrum? If so, how many? Thanks, Yury
  9. K

    The Color of Water: Exploring Wavelengths & Dissipative Absorption

    I cannot understand what is the colour of water.I was reading an Optics book by Hecht,& suppose that we see coluured bodies due to Dissipative absorption.That is taking up of incident photon,converting a part into thermal energy,and releasing the rest energy as another photon.But, ordinarily we...
  10. T

    Calculating wavelengths of photons / photospheric temperatures

    The ionization potentials of HI and KI are 13.6 and 4.3 ev. Calculate the wavelengths of photons that can ionize HI and KI. Calculate the photospheric temperatures of stars that peak at these wavelengths, and hence radiate plenty of photons at shorter wavelengths capable of ionizing these...
  11. E

    Is there a Doppler effect when sound source and object move at right angles?

    "Is there a Doppler effect if a sound source and an object are moving at right angles?" I assume this means that both are moving away from a single point... I thought there would be a Doppler effect because both objects are moving and therefore the sound produced has an effective longer...
  12. M

    Differing wavelengths of equal energy photons and electrons

    If a photon and an electron have the same energy how would i show that their wavelengths differ (relativistically)? Furthermore, how would I find the energy when the difference between the wavelength of the photon and electron is a factor of 4? thanks
  13. T

    Calculating 5 Longest Lyman Series Wavelengths

    How am supposed to calculate the five longest wavelengths of the Lyman series? What values of n are used? I see how you arrive at a definite limit as n goes to infinity, but the five longest? Sort of a dumb question.
  14. U

    The Wavelength of X-Rays Produced by 80kV Electrons

    X-ray tubes used by dentists can have voltages as high as 80kV to accelerate the elecrons to produce the X-rays. What is the most lowest wavelength that can be produced by such electons? This problem seems almost too easy... i need a check \lamba = \frac{1.24x10^3 V^{-1} nm}{80kV}...
  15. O

    Indices of refraction when wavelengths are given

    A parallel beam of light containing two wavelengths, 1 = 400 nm and 2 = 650 nm, enters the silicate flint glass of an equilateral prism with an angle of incidence of 49 degrees. At what angle, relative to the normal, does each beam leave the prism? This seems simple, but previously, I had...
  16. M

    Dealing with wavelengths, frequencies and speed

    Ok, I am working with problems dealing with Speed=(lambda) (frequency). I have a question in determining whether I am solving these correctly. I sometimes get confused as what the wavelength is. 1. A longitudinal wave with a frequency of 25.0Hz travels along a coil spring. If the distance...
  17. J

    How can I use this applet to find the wavelength of a sound wave?

    http://137.229.52.100/~physics/p103/applets/sos_prelab/sos_prelab_pt1.html For my homework, i have to use this java applet and answer the 5 questions at the bottom. Now, i had no problem finding the period, frequency, or length of the tube in terms of the wavelength. But I'm really having...
  18. C

    Photons, wavelengths, and ionization energy

    This is a post-lab question for my chemistry lab but it is kind of physics too so I thought I'd post it here (the other sciences sections don't much response).. It's confusing because the questions are supposed to go along with what we are learning in the chemistry lecture, but we're behind in...
  19. N

    Absorption in 'CMBR' wavelengths - observations? processes?

    A read of the COBE and WMAP teams' papers on the methods they used to produce 'contamination-free' maps (or, to remove all 'foregrounds') is exhilarating. However, unless I missed it, these methods largely address emission in the wavelengths of interest (i.e. those which the various...
  20. M

    Exploring Light Wavelengths from the Sun's Surface

    When we look at the sun, does light emitted from the edges of the sun have a different wavelength than light emitted from the center of the disk?
  21. W

    Transition Energy in ev's Emitted wavelengths in m

    could i get help or a formula for this question please Use the Energy Levels for Hydrogen to calculate the wavelength corresponding to the following electron transition Transition Energy in ev's Emitted wavelengths in m 2->1______ ________x10______
  22. D

    Calculating Speed of Light in Glass Prism

    Hi, could someone please help me get started on this problem. The figure is a right angle triangle with 30-60-90 degree angles (right angle). Can you help, please. Thank you so much. The glass prism shown has an index of re- fraction that depends on the wavelength of the light that enters...
  23. P

    How Does Heavy Hydrogen Affect the Wavelength of the Balmer Series?

    Ok, for this one problem, I'm supposed to figure out the difference in wavelength between the first line of the Balmer series in ordinary hydrogen (M= 1.01 u) and in "heavy" hydrogen (M = 2.01 u). The balmer series is when the lowest n is 2, by the way. I already know that the wavelength for...
  24. D

    What happens when you combine these wavelengths

    Low level transmission of every electromagnetic wave starting from long -wave radio to gamma rays. Thousands of different transmitters not necessarilly being powerful at all, converging on one spot. Wouldnt this create massive electromagnetic spikes here and there? Just as if you were to...
  25. S

    UV Light Wavelengths Reaching Earth's Surface

    Does anyone know the range of the wavelengths of the UV light that reaches the Earth (ground)?
  26. F

    Why do long wavelengths travel further than short wavelengths?

    What is it that allows longer wavelengths to travel further than shorter wavelengths? Is it because of diffraction properties or is it related to the energy of the wave? Or perhaps a combination of several things...? Thanks. Russ
  27. P

    Photoelectric effect and wavelengths

    Here is a question I am having trouble with :rolleyes: , thanks for your help. Electrons are ejected from a photoelectric surface with a maximum speed of 4.20 * 10^5 m/s. If the work function of this surface is 2.55 eV, what is the wavelength of the incident light? This is how i tried...
  28. D

    Spectroscope separates entering light into its component wavelengths?

    What part of the spectroscope separates entering light into its component wavelengths?
  29. W

    Calculating Wavelengths & Refraction Angles for Violet Light

    Here is the question: Violet light has a frequency of 7.5 * 10^14 hz and travels from air to glass at an angle of 30 degrees. The index of refraction for violet light is 1.54. A) Find the angle of refraction B) Find the wavelength in air C) Find the wavelength in glass D) What is the...
  30. B

    How do we use UV values in spectral analysis to identify molecules?

    Wavelengths and dissociation?? I needed some help with this problem. By using photons of specific wavelengths, chemists can dissociate gaseous HI to produce H atoms with accurately known speeds. When HI dissociates, the H atoms move away rapidly, wheras the relatively heavy I atoms move...
  31. D

    Angular seperation between diff wavelengths

    A ray of light consists of blue light(480nm wavelength) and red light(670nm wavelength) is incident on a think piece of glass at 80 degrees. what is the angular separation between the refracted red and blue beams while they are in glass? (The respective indices of refraction for the blue light...
Back
Top