Wavelength Definition and 1000 Threads

Over what approximate time frame does 90% (most) of last scattering occur, minutes, seconds, fraction of a second? How does this time frame relate to the period of the gravitational radiation? If the period of gravitational radiation were short it would washout b-modes? Thanks for any...

If I send a single wave toward a corner won't it bend around the corner? If so, how does the wavelength of that single wave (is wavelength defined for a single wave?) effect how much it bends? Every picture/illustration I have found on diffraction shows a series of lines (plane waves)...

Hi, This is just a quick question. If wavenumber is a variable with some standard deviation Δk, how do I propagate this spread when converting from wavenumber to wavelength? Is it just 2π/Δk or is it more complex than that? Thanks

Is there a relation between the wavelength and the amplitude of a photon (or particle), or all frequencies have the same amplitude? If the latter, why the wavelength affects the way a radiation passes through matter or slits? Thanks.

Hi, I was reading about interference patterns. I was wondering if the classical interpretation of the wavelength of the photon according to maxwell's is the actual wavelength of the photon in the wavefunction? Are the two related? Thanks!

I am doing this problem: (a) Find the speed of waves on a violin string of mass 800 mg and length 22.0 cm if the fundamental frequency is 920 Hz. (b) What is the tension in the string? For the fundamental, what is the wavelength of (c) the waves on the string and (d) the sound waves emitted...

Hello. 2 questions: 1. If a diffraction grating is smaller, approaching infinitely smaller, than the wavelength of incident light, what happens to the diffraction pattern? Does the wave still diffract at all? 2. Wavelength is the distance between two crests of periodic motion. Imagine...

hello If I were to hang a traditional 100W clear glass light bulb from the ceiling, would it radiate 80W (radiant flux), the other 20W lost by air convection/conduction up the wires, or would it radiate closer to 60% or 40% of consumed energy? I can find plenty of figures for the...

Hello - I'm having a difficult time finding this answer anywhere else on Physics Forums. I'm curious if anyone knows, or can figure out, the smallest difference in wavelength that the human eye can notice. For example: Can the human eye detect if a light changes from 568nm to 570nm?

Homework Statement Please see the picture. Homework Equations How do they get this derivation? The Attempt at a Solution I know that lambda = 2L/n and f = nV/2L so I can somewhat rearrange it myself, but I do not know where the square root is coming from.

Hello. I came to this forum to seek help for this question, since I cannot find it anywhere on the internet, nor even books. I have to calculate a maximum of a radiated wavelength of a neutron star. Sorry I don't know how else could I translate it from to English. All I was given is that it's...

Homework Statement Light of wavelength 550 nm in air is normally incident on a glass plate (n=1.5) whose thickness is 1.1 X 10^-5 m. (a) What is the thickness of the glass expressed in terms of the wavelength of light in glass?(b) How many reflected waves will experience the 180 degree phase...

Homework Statement A particle with charge e and mass m_0 is accelerated by a potential V to a relativistic speed. Show that the de Broglie wavelength is: λ = h / √(2 m_0 eV ) √(1+( eV / 2 m_0 c^2 )) Homework Equations E = qV λ = h/p E = √(p^2 * c^2 + m^2 * c^4 ) p = (m_0 * v) / (1 -...

[I could not fit the last "e" into the title] Hi! I am writing a report on TEM, and was asked to consider the effect of accelerating voltage on the resolution. Since resolution in the light microscope is limited by the wavelength of visible light, we obtain much higher resolutions in a TEM...

Homework Statement A cavity at Temperature 6000k has an energy distribution corresponding to a blackbody. We make a small hole in it 1mm in diameter. Calculate the power radiated through the hole of wavelength interval between 550nm and 551nm. HINT: when dλ is small (such in this case)...

I searched for the images of refraction on google images and i saw an image where a laser light was incident on a regular glass slab. Bending of light was clearly seen in the picture. According to Snell's law the refractive index of any particular medium is the ratio of angle of incidence to...

hi friends, can anybody clear my concept about the following sentence. " if we use substrates with higher permittivity, like quartz or GaAs that has been used in previous successful experiments, the unit cell will have smaller unit-to-wavelength ratio".

Homework Statement We place a speaker near the top of a drinking glass. The speaker emits sound waves with a frequency of 3.75 kHz. The glass is 14.1 cm deep. As I pour water into the glass, I find that at certain levels the sound is enhanced due to the excitation of standing sound waves in...

Homework Statement In the figure, sound with a 38.0 cm wavelength travels rightward from a source and through a tube that consists of a straight portion and a semicircle. Part of the sound wave travels through the semicircle and then rejoins the wave that goes directly through the straight...

Homework Statement When a photon is emitted from an atom the atom recoils. The kinetic energy of recoil and the energy of photon come from the difference in energies between the states involved in the transition. Suppose a hydrogen atom changes its state from n=3 to n=2. Calculate the...

Could you please clarify for me how much each of these contribute to the red shifting of light from distant objects? It seems to me that red shifting of light from near by objects i.e. within our galaxy would be affected more by the Doppler effect whereas for intergalactic objects the red...

Homework Statement You decide to become a forensic pathologist because you enjoy working with dead people-they don't talk back-more than with the living. In one murder investigation, you find an unknown liquid in the victim's stomach. To identify this liquid, you pour a known amount of it onto...

Homework Statement A light wave has a frequency of 6 x 1014 Hz. A) What is its period? B) What is its wavelength in a vacuum? C) When the light wave enters water, its velocity decreases to 0.75 times its velocity in vacuum. What happens to the frequency and wavelength? Homework Equations...

1. Units of the Thermal de Broglie wavelength? 2. λ = h / (2*pi*mkT)^(.5) 3. through dimensional analysis i get S (J / kg)^.5 can you even have .5 of a unit?

I was wondering if diffraction of a wave can occur when the gap through which the wave passes is shorter than the wavelength itself. Then I came across this website http://www.talktalk.co.uk/reference/encyclopaedia/hutchinson/m0015966.html Which says that "In order for this effect to be...

Does the wavelength of a photon actually mean wavelength? Because as I understand it, a force field, be it gravity, EM, ect..., has influence at any distance. Theoretically, the field never has an end, reaching out across the whole diameter of the universe, even though the effects would be...

What is the wavelength of a wave that has a frequency of 60MHz?

Homework Statement The threshold frequency of a metal is 3.184 x 10^14 Hz. If a photon of wavelength 368 nm strikes the surface of the metal, what is the wavelength of the ejected electron? Homework Equations f (frequency) = c/(wavelength) Eincident = Ethreshold + KE E=fv(wavelength)...

Homework Statement Hi Two wave superposition with different wavelength , amplitude and frequency u1(x,t)=A1cos(k1x+w1t) u2(x,t)=A2cos(k2x+w2t) a)Show that an amplitude modulation is obtained Homework Equations No relevant equations The Attempt at a Solution...

Homework Statement The following data was obtained upon using a double-slit experiment. Use this data to determine the wavelength of light being used to create the interference pattern. Do this in three different ways. - The angle to the eight maximum is 1.12° - The distance from the slits to...

After going on a ghost tour over Halloween, several people were able to take photos of ghosts seen through an old hotel window, a few stories above our position. This got me to wonder if this was a trick that relied on the way that the digital cameras may be able to detect non-visible...

Hello all. When light goes through one medium to another, its velocity and wavelength change but frequency remains the same. If the wavelength of light decreases, the length between two crests decreases, doesn't that mean there will be more wave hence frequency will have to increase? I tried to...

At the power-line frequency (50Hz), the wavelength of electromagnetic waves in free space is 6,000 km. Similarly, the phase velocity of voltage/current waves is about 4,000 km at this frequency. The question is, why do we bother about the wavelength at all at the power-line frequency, when the...

Why does a 1/4 wavelength antenna have to be 1/4 wavelength? What property of the wave is responsible for this restriction? I've been trying to understand how a 1/4 wavelength antenna works and the best explanation, relatively speaking, was on the following website...

Both source and observer are at rest. If the wind blows from source to observer will the wind affect the wavelength of sound??

is the wavelength equal to the distance between the excited state shell and the rest state shell?

Homework Statement The question is regarding Young's double slit experiment. "Describe the effect, if any, on the separation and on the maximum brightness of the fringes when the following changes are made. ... ... 2) The wavelength λ is increased to 1.5λ, keeping a and D constant...

Hi, I want to ask one question about wavelength. Here is a picture defining wavelength. To get a sinusoidal wave in space, we have to use a sinusoidal voltage source at transmitter, right? I mean if there is a sinusoidal voltage source at the transmitter to create a sinusoidal wave in space.

Homework Statement You and a friend each have one rope. You tie the two ropes together and stand as far apart as possible, each holding one end of the new longer rope and pulling to put it under tension. You then begin moving your arm in such a way as to produce a harmonic wave with a...

Homework Statement At what wavelength does a cavity at 6000 degrees Kelvin radiate most per unit wavelength? Homework Equations $$\rho_T(\lambda)d\lambda=\frac{8\pi{hc}}{\lambda^5}\frac{d\lambda}{e^{{hc}/{\lambda{kT}}}-1}$$ The Attempt at a Solution I'm pretty new to this whole...

Homework Statement Project Seafarer was an ambitious program to construct an enormous antenna, buried underground on a site about 4000 square miles in area. Its purpose was to transmit signals to sub-marines while they were deeply submerged. If the effective wavelength was 1.0x10^4 Earth...

Homework Statement What is the corresponding wavelength, in meters, of an electron moving at 1 m/s? Velocity: 1 m/s Planks Constant = 6.626 069 57 x 10^-34 Mass of electron = 9.109 382 91 x 10^-31 Momentum = unknown Homework Equations We need to find momentum to use De Broglie's equation...

Hi everybody! Just 2 important notes: I don't study physics and so I'm not sure if this question belongs here (but I don't know where should I put it..); second I'm not english native, so ask me if I did not explain somthing enough. My electronic professor told once in my class, that you...

hi what would happen if i modulated two wavelengths with the same intensity modulation frequency? for example if i had 2.0um light and 1.5um light and modulated them both with the same frequency, would sidebands develop around each wavelength? or would they interfer in a more complicated...

(not exactly sure where I'm supposed to post this) i was looking at my UV lamp that i got from walmart. i was looking for a wavelength on there but i only saw "color temperature" i immediately thought Wien's law; so then i calculated the peak wavelength and got 96nm which is on the far side...

I know the visible spectrum,(400nm(violet)-750nm(red)) but I can't seem to find the wavelength of white light, can anyone help me out with this?

I've often read that the emission spectrum of a fluorescent molecule is independent of the wavelength used for the excitation. But what happens in the case of a small Stoke's shift where the excitation and emission wavelengths overlap? If I use a narrow band excitation with a wavelength in...

I read somewhere that Heisenberg described his uncertainty principle by saying that you can't measure position more accurately than the wavelength of light (which makes sense), so Δx > λ. This is what I don't get. He then says that p=h/λ, so Δp > h/λ2 Δλ. He the multiplies and sets Δλ ≈ λ to...

How are the wavelength and frequency of light measured experimentally, are the equal to frequency of their consistent electric and magnetic field motion's frequency...

Hello Dear people,i wanted to know wat actually is wavelength?? I have heard all the definations most of them says its difference bw two crest or trough..that is ok.most of the people understand wavelength as path of particles while travelling..is it true?? wat is meant by wavelength of...