Wavelengths Definition and 224 Threads

Radio waves can go through walls and x Rays go through body tissue but the visible spectrum is blocked by both . Why is this the case?

Hello, As we all know, speed of light of different wavelengths (let's say red and blue) in vacuum is same. However, in medium (like glass) it's different and depends on a wavelength and a refractive index. Let's say we send a short pulse of white light incident into a piece of glass (of length...

I was wondering which specific wavelengths of light cause the photolysis of water to happen.

During optical pumping in a laser, is the wavelength of light that corresponds to the transition from the metastable state that yields the laser light removed? Otherwise, wouldn't a population inversion not be possible as these photons from the optical pumping would cause stimulated emission...

In fluorescence microscopy, dichroic mirrors reflect light under a critical wavelength (used to excite the sample) and transmit light over a critical wavelength (emission light from the sample). Are there mirrors that reflect two different wavelengths of light and transmit the rest? Essentially...

Am just wondering what the currently accepted measurement standard is for the Lyman series spectral lines. At NIST I find the following set of measured wavelengths (nano meters): 91.9342 92.0947 92.3148 92.6249 93.0751 93.7814 94.9742 97.2517 102.5728 121.56701 At...

Homework Statement If λCu is the wavelength of Kα X-ray line of copper (atomic number 29) and λMo is the wavelength of the KαX-Ray line of molybdenum (atomic number 42), then the ratio λCu/λMo is close to 1.99 2.14 0.50 0.48 Homework Equations De broglie relation λ = h/p The Attempt at a...

Homework Statement Water waves in a shallow dish are 6.0 cm long. At one point the water oscillates up and down at a rate of 4.8 oscillations per second. a. What is the speed of the water waves? b. What is the period of the water waves? Homework Equations frequency = 1/period Speed =...

Homework Statement Using the two-dimensional wave interference pattern shown and the two equations involving path difference, complete the following. i) measure the wavelength of the waves ii) measure the distance between sources iii) measure the path distance from each of the sources to the...

What would the Wavelength of these particles be? Also if you could, what would the amplitude be, I'm guessing 0.

So this is basic question but the more I read the more I am confusing myself! I was assuming that the wavelength of a photon was the same wavelength as the associated probability amplitude (although a complex number). So to make constructive interference it means one path takes say ten...

Hey everyone so I'm having some trouble figuring out how to approach this question. I don't need a step by step solution just an idea of how I should approach the question and maybe some specifics on how to apply needed concepts such as reduced mass. Thank you. "Assuming positronium were a...

Hi all, I've read that when light undergoes refraction into a medium with higher refractive index it changes speed and this is explained by the electrons of the medium absorbing the photon energy, they hold onto it then eventually re-emit the light if the frequency of light doesn't match the...

I was just working on a problem that asked me to show that Plank's Law for black body radiation is approximately equal to Rayleigh-Jeans Law, which expresses the energy density of black body radiation as a function of wavelength. I was to show that this relation is only true at high wavelengths...

I want to know that ,I have read in many books regarding compton's effect that a photon collides with an electron and this collision is a head-on collision,but if this is a head-on collision then why both these particles are deflected by making a respective angle,don't they should move forward...

This question is about the interference pattern observed when the waves from two microwave transmitters interfere. The first parts of the question involve the wavelengths of microwaves being the same for each transmitter. For the last part the question proposes that the wavelength of one of...

Can anyone speak on the spectrum of sunlight reaching the upper atmosphere and the surface ? Specifically I interested in finding out if there are any IR wavelengths disproportionally represented when compared to the original source. Please limit responses to constructive ones.

Suppose you have a source of light that emits light with a wavelength of 2 meters, and you set the device to be turned on and switched off alternately. You also set it so that each interval the device is turned on is only long enough for 1 meter to be emitted (1/2 a wavelength). Do you ever...

Our Vision System should be sensitive to one specific term, they do not mean the same, one is related with geometry factors (wavelength) while the other is related with beating stimuli (pulse) The frequency of light (f) is constant from media to media, the same as it is in vacuum, wavelength...

I hope this is the right place to ask this. It is an experiment question. I have a 785 nm laser and a 1550 nm laser and I need to converge them down to a point. Now I could just manually align the lasers on the same XY-plane and have them hit that spot, but for reasons I don't want to...

Homework Statement Consider a string of length L held fixed at both ends. The string can be shaken up and down and, at certain frequencies, the result will be a standing wave pattern on the string. Find the five longest wavelengths (call them λ1, λ2, λ3, λ4, and λ5) of the standing wave...

Homework Statement The questions is... Coherent light with wavelength 597nm passes through two very narrow slits, and the interference pattern is observed on a screen a distance of 3.00 m from the slits. The first-order bright fringe is a distance of 4.84 mm from the center of the central...

If I have an atom with energy levels of -4 ev, -2 ev -1 ev and 0 ev and I radiate it with photons which cover a continuous range from 0 to 2 ev is it not possible for a 2 ev photon to move the electron from -4 to -2 and then a 1 ev photon to move it from -2 to -1 and then a 2 ev photon to free...

So Rayleigh scattering says that higher wavelengths of light are scattered more than lower ones - but why don't we ever see the scattered wavelengths anywhere? Is it just because when they're scattered they have lower intensities and are outshined by blue?

Homework Statement I've attached the problem Homework Equations d*sinθ=mλ The Attempt at a Solution I've tried a couple of methods. I considered solving for m when θ=90 degrees => sinθ=1 because 90 degrees is the highest possible angle and will (in my mind at least) yield the highest order...

Homework Statement A grating has 1070 lines per centimetre, and a flat screen is perpendicular to the ray that makes the central peak of the diffraction pattern. The screen is 3.20 m from the grating. If light of two wavelengths, 630 nm and 705 nm, passes through the grating, what is the...

Something that bugged me when doing this lab. Standard little glass vials of gas, toss it in a 5kV potential make pretty color, look through diffraction grating see the individual wavelengths that are the finger prints of the element. My question however are all wavelengths equally...

This question is based on a modern physics lab I'm working on, and it's conceptually killing me. 1. Homework Statement For hydrogen, compare your measured wavelengths to the predicted wavelengths for hydrogen. Assuming the lower level is the same for all the lines you observed in the...

The question is: the wavelength of a spectral line on the left edge of Jupiter's equator is 499.98 nm, and the right edge is 500.02 for the same spectral line, what is the length of jupiter's day (in hours)? I know that its 10 hours but I need to show my work. I tried using many different...

Hey there, I'm new here mainly because I realized how deficient my ability to think in Physics/Math based scenarios really is, plus if I'm going to stay in Premed I need to pass a Phys 101 course in 1st year. So, my question is this.. The windows in an office tower are coated with a film...

Dear All, thank you for your attention. I am a Biologist and I was wondering if it is possible to translate absorbance λ values into a refractive index value? I found out about the sellmeier equation however it appears to require coefficients that have to be experimentally determined...

My question is... Does the wavelength of light (in vacuum space, of course) suffer changes as it approaches to a gravity field, or simply stays the same?

recently i have been thinking about how colors add when you have 2 different light sources of color and put the streams together, such as taking red and green beams and crossing them to make yellow. i was looking at wavelengths to determine if there was a mathematical way to say what color would...

This is my first forum post so I apologize in advance if I do not provide enough detail, speak clearly enough, or violate some forum etiquette. I have a few questions here all relating to the same thing so hopefully this isn't worded poorly or too much. When light strikes a surface, the...

I understand the derivation and calculation of de Broglie wavelengths. What I don't understand is what exactly they are. What does the wavelength of a particle mean? Does it mean the wavelength of its probability wave, or some other kind of wave? The idea of wave-particle duality for EMR...

Homework Statement Assume that the total energy E of an electron greatly exceeds its rest energy E0. If a photon has a wavelength equal to the de Broglie wavelength of the electron, what is the photon’s energy? Repeat the prob- lem assuming E = 2E0 for the electron. I need help with the first...

Homework Statement See attached image Homework Equations single wavelength mλ=dsin(θ) diffraction grating: d*(sinθi+sinθm)=mλ y/L = sinθ The Attempt at a Solution red = 656 nm blue = 486 nm L = 1.7 m I really do not know what to do. I tried 656-486 = 170 nm so...

Hello, what is referred to that every moving body has an associate wavelength ? thank you

A blackbody radiator emits radiation across the entire radiation spectrum. The "temperature" of the blackbody radiator (measured in kelvin) can be directly calculated from the peak wavelength of its radiation using http://en.wikipedia.org/wiki/Wien's_displacement_law"]Wien's[/PLAIN]...

Homework Statement In the hydrogen atom, the electron jumps from the n = 1 level to the n = 4 level. a. During this transition from n = 1 to n = 4, is a photon emitted or absorbed? b. What is the change in energy of the electron? c. State the transition in words. d. What is the wavelength...

Homework Statement Calculate the bond length for the NaCl molecule given that three successive wavelengths for rotational transitions are 23.1 mm, 11.6, mm and 7.71 mm. Homework Equations I = h*wavelength/4pi*speed of light. The Attempt at a Solution I don't understand how to...

I am intending to perform extended absorption fine structure (EXAFS) experiments on a thin film in order to investigate the near order around Europium ions. The thin film is going to be deposited on a silicon substrate, and the question is in reality related to how thick the substrate should be...

Hi I know that in the Bohr model, electrons move between energy levels, but you don't hear much about the electron's wavelength at each particular level. If we assume the orbits contain an integer multiple of wavelengths, you get the usual $$2\pi r=n\lambda,$$ so, based on the expression for...

Hi! I have worked on this for a while and cannot seem to get a reasonable answer. I have been given the Luminosities of planets at different wavelengths and I need to determine the Temperature. I re-arranged Planck's equation to find T but I keep getting really low temperatures Planet A...

I was thinking today about whether or not mirroring could be altered to reflect only certain wavelengths of the spectrum? I couldn't think of specified way to do such a thing, thought maybe some more adapted minds could lend some advice. Thanks for any help on the topic.

Homework Statement Compute the wavelengths in fused silica and in silicon for photons whose free-space wavelengths are 800 nm, 1300 nm, and 1550 nm. Homework Equations This is the problem, I'm not sure what equation to use and the textbook does not seem to say, well what little I have of...

I have calculated the wavelength of a line that would be observed in a spectrum from Andromeda where speed and λ0 were known, using the formula z =∆λ/λ0 and z=v/c. I obtained a value smaller than λ0 because Andromeda display a blue shift. After I calculated the same wavelength pretending that...

Hi All, I'm trying to find a sine function that models the cyclic and seasonal nature of retail sales across the years. I've tried several combinations including some basic attempts at complex plots of sin(x), but am now starting to wonder if there is even a simple solution to the problem...

Question 20 from our final I just took (Analytical Chemistry UF). "You may recall that the wavelength of the sodium D1 line in vacuum is 589.7558nm. In air it becomes 589.5924nm. What is the difference in frequency for these two wavelengths." I said 0. All the other people did the...

The earlier thread was closed for some reason. It prompted this question: Given the formula for CMB temperature Tobs = Tem/(1+z) (analogous to the formula for z) it seems the age of the universe at the emission of the CMB would have been about 12.5 Myr (if 13.75 Gyr presently), not 380,000...