X-ray Definition and 285 Threads

Homework Statement The atomic number of tantalum is Z = 73. According to the Bohr model, what is the energy (in joules) of a K X-ray photon? Homework Equations Energy= -(13.6 eV)Z^2/n^2 The Attempt at a Solution I don't know what to use for n

1. Question A cubic crystal of interatomic spacing of 0.24 nm is used to select gamma–rays of energy 100 keV from a radioactive source containing a continuum of energies. If the incident beam is normal to the crystal, at what angle with respect to the incident beam do the 100 keV...

Hi all, Does anyone of you know the ways in which dose administered to a patient can be minimised while still obtaining a useful X-ray image ?

I had recently stumbled upon a computer program that can automatically add missing hydrogen atoms to protein structures from files from the protein data bank. (due to the hydrogen atom having only 1 electron, hence making its electron density too low to be detected by X-ray crystallography...

Hello, I've got some questions about an experiment I did about the spectrum of a x-ray beam which I measured by looking at the diffraction off a NaCl crystal of the beam coming from a tungsten anode as a function of the scattering angle. The measurement I got was something like the following...

Hey all!, I'm working on a project in which I have to design the shape of a mirror to focus X-rays. This is basically what I've done so far so far. I've found that if you use a parabola mirror it will focus parallal rays, but not off-axis ones. If you then add a second mirror in the form of...

This is one of the questions on my regular worksheets we have before our tests: A fast-moving electron traveling through a vacuum tube slams into a piece of steel, coming abruptly to rest and emitting an X-ray photon with an energy of 7.90×10-16 J. What is the wavelength of the photon? I...

hi, i'm having trouble with a problem regarding X-ray crystallography. the question is as follows: ---------------------------------------------------------------------- In general, crystals can have various symmetry elements: rotation, translation, reflection, etc. however, you never...

I was wondering why Henry Moseley ploted \sqrt{f} vs. Z instead of just f vs. Z. I'm guessing it is because this way, the graph of \sqrt{f} vs. Z would be linear? But if it was just f vs. Z, wouldn't the equation just be exponential? Also, what is the significance of the L seriese and the K...

Hello. I took a course in Ultrasound and I wonder why dentists don't use that instead of X-ray. The patient only need to fill his/hers mouth with water and then it is possible to use Ultrasound Scans in the mouth of the patient without any jonisating radiation. It could even be possible...

It's common practice in radiography, especially medical radiography where radiation doses are relevant, to use a fluorescent screen to expose photographic film, rather than rely on the effect of x-rays on the film itself. I understand the concept of fluorescence and the overall photon...

Hi Group I have a question about x-ray spectra. If we look at a spectrum from a typical x-ray tube with a wolfram-74 anode, we get a spectrum http://ie.lbl.gov/xray/w.htm with two lines resulting from K-shell ionisation. Question : Why is it (mostly) the electrons from the K-shell that are...

Perhaps this a stupid question but I am posting it anyway because I did not find a better place to ask :biggrin: . When X-ray photographs are taken of the bones, we get the "negative" image on the photographic plate. Is it possible to develop the "positive"? If so, what will the image look like?

I was given the following question: A crystal of hydrogen atoms and a crystal of lead atoms have exactly the same crystal structure, including lattice constant. How can they be distinguished by x-ray diffraction? The solutions say that the beams diffracted off the lead crystal would be much...

how do you find the kinetic energy of an electron whose de Broglie wavelength is the same as that of a 100keV x-ray?

if anyone own that ,please have it shared OK?Thanks!:smile:

In x-ray diffraction with crystals, what actually happens with the incident x-ray beem or photon? scattering occurs due to which atoms (plane) of the crystal?(can it penetrate into the interior of the crystal?) why doesn't the reflection occur with big wavelengths?

in my modern physics textbook 6/E by arthur beiser, the formula for x-ray production is written as (namdamin)=1.24*10^(-6)/V V*m is that a typo? how can namda have units of V*m?

I'm watching a program on discovery channel now about a girl in russain bloc who can actually, get this, see through people and diagnoise their problems! She lives in poverty, and people come to her from all over russia for help since some of the doctors there cannot help her. Has anyone else...

is ultrasound technology cheaper compared to x-ray technology? is it easier to construct? for example the ones to probe foetus in pregnant females. what is the advantage for using ultrasound for probing foetus compared to x-ray, apart from safety issue? thanks.

Could anyone tell me what the difference between Q-spacing Bragg-spacing D-spacing and repeat distance is? I've always thought that they were same, but seemingly not? What is the realtionship, what is Q? Its keeping me up at night!

bragg spacing? how does it differ from d-spacing? and where does q fit in? And finally are all of these directly related to the repeat distance?

just been learning how to produce x-rays by firing electrons at heavy atoms, but i am a tad confused about the x-ray spectra graph with 'intensity' on the y and 'wavelength' on the x. it shows that the minimum wavelenth is produced wen intensity=0. how is this possible?

Hey! Of course you can help me! :) I need some information about HOW TO MAKE X-RAY VISIBLE. I know that it depends on the atomic number, but I need it more specific, do you know where I can get some information about my problem? I don't want you to write an essay for me, but I really need some...

is there anyone on here who could help me out with either of these?

Need help with "X-ray production" Hi everyone. i am in 12th grade now. im having problems with the production of X-ray... Can someone tell me how X-ray is generated? From the very begining...to the charateristic raditaoin and the Bremsstrahlung Radiation...to the intensity graph (the one with...

I have a problem saying: X-rays having an anergy of 300KeV undergo Compton scattering from a target. The scattered rays are detected at 37 degrees relative to the incident rays. Find the (a) Compton shift at this angle. Now i have the angle.. but i figure i need the wavelength of the...

Faster than c! hi I read that the refractive index(n) for X-rays in meterials are less than 1(very little less than 1). I got confused ..I am using X-ray reflection at the moment. But I am not convinced by the fact that n<1 means faster than c(velocity of light in vacuum or in air)! hope...

Here's an interesting problem: Find the atomic spacing in a crystal of rock salt (NaCl). The density of rock salt is 2.16 * 10^3 kg/m^3 and the average masses of the Na and Cl atoms are respectively 3.82 * 10^-26 kg and 5.89 * 10^-26 kg. Now I know that density (Rho) = mass/volume and 2d sin...

can anyone explain howz x-ray been produced. thank you

http://www.astronomy.com/Content/Dynamic/Articles/000/000/001/604djcxv.asp XMM-Newton studies the X-ray universe from Earth orbit. ESA A mystery that has been haunting the fields of physics and cosmology has just grown deeper. Dark energy, that stealthy ghost that lurks in the...

Does anyone remember when Pravda only told the government's lies? I am posting this as a reminder that IMHO, Pravda is not a valid news source. http://english.pravda.ru/science/19/94/377/11797_phenomenon.html

I'm having a little bit of a problem with this one. Here's the question: X-ray pulses from Cygnus X-1, a celestial x-ray source, have been recorded during high-altitude rocket flights. The signals can be interpreted as originating when a blob of ionized matter orbits a black hole with a...

Heres the problem: An x-ray tube used for cancer therapy operates at 4.0 MV, with a beam current of 25 mA striking the metal target.Nearly all of this power is transferred to a stream of water flowing through the holes drilled in the target. What rate of flow, in Kg/sec, is needed if the...

" To the eye, she is dressed in a skirt and blazer in dark, businesslike colors. On the monitor she is naked..." http://news.yahoo.com/news?tmpl=story2&u=/030625/168/4i6lv.html&e=1&ncid=1756