NSX Posted February 2, 2004 Posted February 2, 2004 I know Snell's Law applies to light, but does it apply to other forms of electromagnetic radiation as well? ie. the behaviour of the waves through different mediums/materials?
NSX Posted February 2, 2004 Author Posted February 2, 2004 http://www.scienceforums.net/forums/showthread.php?s=&threadid=2280 Or google it. It explains the behaviour of light when it passes through one medium into another. I was wondering if the Law applies to EMR in general.
-Demosthenes- Posted February 2, 2004 Posted February 2, 2004 "Ryerson Polytechnic University - Bachelor of Engineering" Way otta what I can understand. I can try again tomorrow again though.
NSX Posted February 2, 2004 Author Posted February 2, 2004 -Demosthenes- said in post # :"Ryerson Polytechnic University - Bachelor of Engineering" Way otta what I can understand. I can try again tomorrow again though. hehe Thanks for trying anways.
YT2095 Posted February 2, 2004 Posted February 2, 2004 yes, EMR is effected by materials, obviously by different materials though, as a lens to focus light is considerably different to a lens that focuses Radio waves. Gamma rays are effected by materials also, it`s that effect that`s exploited in taking an X-Ray
-Demosthenes- Posted February 2, 2004 Posted February 2, 2004 Okay, I thought it was a bunch of equations! But it's not that hard! I'd imagine all things on the Elctromagnet spectrum: Radio waves, infrared, visible light, ultra violet, and x-ray (I think I forgot one.??)would behave different though different mediums. Isn't an x-ray blocked be lead? and defracted of of bones a little?? But if they did they would be just a little bit different from each other.
YT2095 Posted February 2, 2004 Posted February 2, 2004 "Isn't an x-ray blocked be lead?" it can be, sure. it all depends on the thickness really
-Demosthenes- Posted February 2, 2004 Posted February 2, 2004 Ah, like radiation blocked be gold foil: It was only blocked at certain points because it was block by the gold(Au) nucleus of the atom. So it it was thicker it would have more of a chance to hit a nucleus and be stoped, am I right?
YT2095 Posted February 2, 2004 Posted February 2, 2004 that sounds about good as a working example the gold foil IIRC was something to do with Alpha radiation.
YT2095 Posted February 2, 2004 Posted February 2, 2004 Good question, I`ve no idea if it is or just a physical phenomenon as it`s emited by isotopes rather than electronic aparatus, unlike Gamma radiation that can be generated by either. I`de be interested in knowing that too
-Demosthenes- Posted February 2, 2004 Posted February 2, 2004 ISn't alpha just an electron moving around? Or am I thinking of somemthing else?
YT2095 Posted February 2, 2004 Posted February 2, 2004 something else Alpha is something to do with Helium Nuclei, I`m no expert either
-Demosthenes- Posted February 2, 2004 Posted February 2, 2004 Oh! I was so sure! I'm going to google a bit.
-Demosthenes- Posted February 2, 2004 Posted February 2, 2004 Beta is an electron! Alpha is teo protons and two neutrons bound together. Gama rays are waves, thats why they are in the spectrum! I'm an expert now!
wolfson Posted February 2, 2004 Posted February 2, 2004 Mr expert (lol), If you look at the Periodic Table, you can see the affect of these types of radiation, i.e. Alpha emission basicly takes 4 of the mass number and two of the atomic number, i.e. emitting a He atom, and Beta emission emites a e-.
-Demosthenes- Posted February 2, 2004 Posted February 2, 2004 Cool! I don't completely understand Gamma rays though. All the other's are particals and Gamma is a wave? How is it emitted, what is the effect of it. Thanks!
greg1917 Posted February 3, 2004 Posted February 3, 2004 Alpha particles are in essence helium nuclei (thats 2 protons and two neutrons emitted s a 2- ion) that have been emitted by an unstable isotope. Due to being a large bulky particle, they can be completely blocked by tissue paper. Beta particles are high energy electrons that were emitted when a neutron turned into a proton within the nucleus of an unstable isotope. Can be absorbed by a few centimetres of aluminium. Gamma rays are very very short wavelegth EMR that can be emitted by an unstable isotope 'rearranging' itself. Depending on activity of source, could require think lead plate for effective shielding. All three types of radiation can ionise surrounding materials. Extreme exposure will result in radiation poisoning, increased risk of cancer and general nastiness.
Dave Posted February 3, 2004 Posted February 3, 2004 YT2095 said in post # :that sounds about good as a working example the gold foil IIRC was something to do with Alpha radiation. The gold foil was Rutherford's Alpha scattering experiment. He basically fired helium nuclei (alpha particles) at an extremely thin (couple hundred layers of atoms) piece of gold. Using the model of the atom that was thought to be right at the time (plum-pudding model), all the alpha particles should have passed straight through the foil. But he measured a very small minority (like 1/10000 attempts) that were deflected back on themselves. So he was able to determine that the current model we use today of the atom was the correct one, not the other one. That's probably a crappy description, but if you want to learn more, just google it.
NSX Posted February 4, 2004 Author Posted February 4, 2004 dave said in post # :So he was able to determine that the current model we use today of the atom was the correct one, not the other one. That's pretty good description. But we use Bohr's model now.
Radical Edward Posted February 4, 2004 Posted February 4, 2004 snells law works for all waves. but of course it depends on the properties of the medium in order to get your wavefunction correct. for example, if you set up waves in a shallow pool of water, and then put a block of glass (or anything else) in the water, you can see the wavelength change over the glass block.
YT2095 Posted February 4, 2004 Posted February 4, 2004 dave said in post # : The gold foil was Rutherford's Alpha scattering experiment. He basically fired helium nuclei (alpha particles) at an extremely thin (couple hundred layers of atoms) piece of gold. Using the model of the atom that was thought to be right at the time (plum-pudding model), all the alpha particles should have passed straight through the foil. But he measured a very small minority (like 1/10000 attempts) that were deflected back on themselves. So he was able to determine that the current model we use today of the atom was the correct one, not the other one. That's probably a crappy description, but if you want to learn more, just google it. no not al all, that`s basicly the way I learned it 20 years ago too I just didn`t rem all the details, my teacher then went on further to explain that it would be the equiv of a tank artillery round bouncing back of a sheet of toilet roll, there must have been something VERY dense in there for it to ricochet off (the Nucleus). it`s not a crappy explaination
Radical Edward Posted February 4, 2004 Posted February 4, 2004 it is not so much density that is the issue here, the point is that there is a concentrated area of positive charge in there, rather than a distribution of positive and negative charges as in the plum pudding model.
NSX Posted February 8, 2004 Author Posted February 8, 2004 Radical Edward said in post # :it is not so much density that is the issue here, the point is that there is a concentrated area of positive charge in there, rather than a distribution of positive and negative charges as in the plum pudding model. Plum pudding?
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