Ray Definition and 517 Threads

  1. jssamp

    Displacement of emerging light ray

    Homework Statement A light ray is incident on a flat piece of glass with index of refraction n. Show that if the incident angle θ is small, the emerging ray is displaced a distance d = tθ(n - 1)/n form the incident ray, where t is the thickness of the glass and θ is in radians. Homework...
  2. A

    Which is Brighter: Gamma Ray Bursters or Quasars?

    Okay, so this may be a little bit of a trivial question, but I've read conflicting information and found myself confused as a result. I've read from several sources (wikipedia, books) that GRB's are the most luminous events known to occur in our universe. However, I've also read that...
  3. O

    What Is the Angle of Refraction for a Light Ray Incident on Glass at 30 Degrees?

    Refraction -- A light ray is incedent on a block of glass at an angle of 30 degrees Homework Statement A light ray is incedent on a block of glass at an angle of 30 degrees,what is the angle of refraction. Given: glass: 1.47 incident angle:30° Homework Equations π1 sin θ1 = π2 sin...
  4. aleemudasir

    Is Snell's Law valid even when incident ray is Normal to the surface?

    According to the Snell's Law refractive index n21= sin i/sin r, but when we use this equation while having a incident light normal to the surface of lens or any other refracting surface it becomes 0/0. So how can we define Snell's law in this situation?
  5. J

    J.J. Thomson's cathode ray experiment

    In Rohlf's Modern Physics textbook it reads: "The value of q/m for the electron determined by Thomson wan substantially smaller than the values of q/m determined by electrolysis, that is, q/m for the electron is much smaller than for ionized atoms. There were two extreme possibilities: (1) The...
  6. D

    Cathode ray create interference pattern?

    If I were to construct a cathode ray tube in which the beam of electrons was focused on a double slit, behind which was a screen of phosphorous, could I create an interference pattern? Could this setup be made at home? I imagine making the slits would be the most difficult part. Or is this...
  7. M

    Measuring the velocity of cosmic ray muons

    Homework Statement I'm participating in a worldwide undergraduate-level experiment to measure cosmic ray muons. I've got the data, and am in the process of writing a paper (called a poster for some reason), which details the experiment, procedure, and results. Right now I'm trying to...
  8. S

    Exploring Gamma Ray Bursts: Causes, Effects & Interest

    I've been reading about gamma ray bursts (GRBs) lately and have found them to be pretty interesting. As far as I have read, it appears that we still don't know much about what actually causes them, or rather, how the "internal engine" works. The most popular idea for longer lasting GRBs is a...
  9. M

    Cathode Ray Tubes: Understanding the Role of Cathodes

    From my current understanding, a cathode is an electrode which has conventional current flowing OUT of it (or electrons flowing INTO it) while an anode had conventional current flowing INTO it (or electrons flowing OUT of it). From this definition, I don't understand why the electrode which...
  10. A

    X-Ray Photography Safety: Risks, Precautions, and Resources

    Hi, (I'm not native in English, sorry for if bad English) Some background: As a programmer I got more and more distance with physics. I bought a US x-ray tube off ebay to step to a hobby project that naturally keeps me on with refreshing physics knowledge. After the tube came, I jumped...
  11. N

    What would happen if the sun was hit by a gamma ray burst?

    Now I am wondering what would happen to the sun if it was hit by the nearest gamma ray burst (I believe the nearest one is 6.7 Light years away). Now I understand that a gamma ray burst is going to be more radiation than what the sun produces in its lifetime. I also know that the sun is just one...
  12. Q

    Bragg's diffraction x ray flourescence

    i understand that when we shoot x-rays at a object, it will scatter in accordance to bragg's reflection law. as such we position the detector as per the picture below my question is , for the production of characteristic x-rays, does bragg's reflection law still holds? and why does...
  13. N

    Geometry problem: How to show that the ray is well-defined?

    Show that the ray is well defined / independent of ruler placement. Ruler placement postulate says Given two points P and Q of a line, the coordinate system can be chosen in such a way that the coordinate of P is zero and the coordinate of Q is positive. I know you can place ray AB where B can...
  14. B

    Fields in Physics assignment question about electron beams in a cathoe ray tube

    Homework Statement Ok so we have been given a diagram of a cathoe ray tube, with relevant data on it. The second question asks to "calculate the speed of the electron, using data from the first question". I need to make sure the answer is correct as it leads into many different questions...
  15. P

    Archived Displacement and Momentum, particle in cathode ray tube with variables

    Homework Statement In a cathode ray tube (CRT) used in older television sets and oscilloscopes, a beam of electrons is steered to different placed on a phosphor screen, which glows at locations hit by electrons. The CRT is evacuated, so there are few gas molecules present for the electrons to...
  16. V

    Calculate Image Diameter of Sun in Concave Mirror with Given θ and f

    θHomework Statement The sun of (diameter D) subtends an angle of θ radians at the pole of the concave mirror of focal length f. The diameter of the image of the sun formed by mirror is _____ Homework Equations 1/v+1/u=1/f The Attempt at a Solution confused with question. Either i...
  17. T

    Back-projected ray in homogeneous coordinates

    suppose I got a projective camera model. for this model I would like to back-project a ray through a point in the image plane. I know that the equation for this is the following: $$ y(\lambda) = P^+_0 x_0 + \lambda c_0 $$ where P^+_0denotes the pseudoinverse of the camera matrix. x_0 the...
  18. mrspeedybob

    Traveling parallel to a ray of light through a gravitational field

    I was thinking yesterday about a scenario where a ray of light passes a massive body and is deflected. If I were in a rocket moving at the speed of light along the same trajectory, I should follow the same path through the gravitational field and so should observe the ray of light to be...
  19. D

    Refraction of Incident Ray Through Water

    Homework Statement Plot a graph of sinθ versus sinθ' where θ is the incident ray and θ' is the refracted ray and use the graph to determine the index of refraction of distilled water, the medium through which the incident ray passes. Draw the graph without including the origin as a data...
  20. phosgene

    Ray tracing diagram for white light moving through glass

    Homework Statement White light is incident on a sheet of glass as shown below. Complete the ray tracing diagram. Homework Equations n1(sinx)=n2(siny), where n = the refractive index of the medium. The Attempt at a Solution The ray on the bottom is hitting the glass at 90 degree angles...
  21. P

    Understanding Cathode Ray Discharge and Electron Knockout

    When a high voltage is applied across the electrodes of the discharge tube, and the pressure of the gas inside the tube is lowered, the electrical energy knocks out some of the electrons from the atoms. These constitute the cathode rays. How does electrical energy knocks out electrons is...
  22. R

    X ray questions:What material is suitable in windows for hard X-rays?

    What material is suitable in windows for hard X-rays? What material would you choose as reflective coating of X-rays mirrors for radiation at 200 eV? Why?
  23. N

    Gamma ray spectroscopy of deuteron formation

    For my advanced physics lab course this semester, I recently conducted an experiment using a hyper-pure germanium detector to measure the energy of gamma rays released upon the formation of deuterium (DF). Essentially, I used a neutron source to bombard a hydrogen rich target (used both...
  24. hagopbul

    Help in a tube about a laser ray

    i need a equation that discrip the movement of laser ray in the tube in a way that it won't get out
  25. V

    Building a simple cosmic ray detector

    During a visit to CERN (more precisely:ATLAS) I got the idea of building a cosmic ray detector from the guide (who was a full time researcher there). The detector would look like a small rectangle with colored stripes going trough it about once a few seconds to signal the path of the muons...
  26. F

    Can Alternative PMTs and Cheaper Materials Work in Cosmic Ray Detector Designs?

    I am building a cosmic ray detector and I am following these designs: http://www.lbl.gov/abc/cosmic/documentation/CosmicDetector2-0.pdf I have a few questions for those who may be familiar with this. a) In the parts page (http://www.lbl.gov/abc/cosmic/parts.html) I see that the price for the...
  27. L

    Gamma Ray Experiment: Measure Voltage, Linear Absorption Coefficient & Test 1/r2

    Homework Statement In my honours lab we had to perform the Gamma ray experiment in which we have to measure the operating voltage of a Geiger Muller tube for a radio active source say Cs-137. With this we want to measure the linear absorption coefficients of lead and aluminium. Test the...
  28. K

    How to calculate the Poincare dual of a ray on R2-{0}?

    S={(x,0)|x>0} on R^2-{0},I need to calculate the closed Poincare dual of S. Assume \omega=f(x,y)dx+g(x,y)dy on R^2-{0} have compact support.Then we need to find a form \eta in H^1 (R^2 - {0} ) satisfying \int\limits_S {i^* \omega = \int\limits_M {\omega \wedge \eta } } , The book...
  29. A

    Could a star survive a direct hit from a gamma ray burst?

    What would happen to a star if it took a direct hit from a gamma ray burst? For example if a gamma ray burst from a supermassive black hole at the center of a galaxy hit a star, would the star survive? If so, how would the grb effect the star? If not, would the star explode...
  30. M

    What is the formula for the angle of deviation in a thin prism?

    I finally found something about thin prisms on the web I don't understand whether the angle of deviation depends on a the angle of incidence in a thin prism or not? Is the thin prism always in the position of minimum deviation?
  31. L

    X ray production - doubts in the principle involved

    X ray production -- doubts in the principle involved Homework Statement In x ray production, air molecules are ionised due to presence of very high electric field within the tube and positive ions are attracted to the cathode C and due to their impact electrons are emitted from the cathode...
  32. L

    Electrostatics problem (electron's motion in cathode ray tube)

    Homework Statement Homework Equations Fq=E*q kinematics equations... The Attempt at a Solution The problem is that in the end I get a value ABOVE the mid-axis instead of below. I don't know what I'm doing wrong. Please check my reasoning. Stage 1: While it's in between the plates where...
  33. T

    How much will a ray be deviated ?

    How much will a ray be "deviated"? So my terrible phys prof presented this question but failed to answer it and I have become very curious of the answer after failing to answer it several times. Here is a quick paint drawing of my question...
  34. M

    Trajectory of an electron in cathode ray tubes

    Why is it that an electron traveling under the influence of a magnetic field (i.e electron going from left to right and B field going into the page) will travel in the arc of a circle yet when an electric field alone is applied (say up page and the direction of motion of the electron is the...
  35. M

    Does a gamma ray photon have less energy than a radiowave photon?

    I'm wondering because the gamma ray photon is smaller yet it has a higher frequency. Is it because the amount of energy that passes a single point in a second for a gamma ray is higher than that of radio waves, since a lot more photons are passing that single point that in other em radiation?
  36. Simfish

    Do nearby gamma ray busts/supernova damage *more* than just the ozone layer?

    http://en.wikipedia.org/wiki/Near-Earth_supernova So we know that many people are putting hard constraints on the galactic habitability zone based on the presence of nearby supernova/gamma ray bursts. But if they *only* affect the ozone layer, then I doubt that it's as hard of a constraint as...
  37. L

    Is a lens necessary for producing focused images?

    But if this is so, then in these photographs: http://en.wikipedia.org/wiki/Bubble_chamber http://en.wikipedia.org/wiki/Cloud_chamber the "particle track - line of bubbles" shouldn't be able to be photographed so defined, but blureness should be photographed instead, since-if no lens was used...
  38. A

    J.J Thompson's Cathode Ray Experiment

    When Thompson conducted his cathode ray experiment, how did he know that the negatively charged electrons were so small? He knew that they were deflected in measurable ways by electric and magnetic fields, so he concluded that they must have a very small mass to charge (m/e) ratio. But that...
  39. N

    How Do Cosmic Rays Travel Through Earth's Atmosphere?

    Homework Statement A cosmic ray travels 60km through the Earth's atmosphere in 400μs, as mesured by experimenters on the ground. a. Calculate the relative velocity between the cosmic ray's intertial reference grame and the Earth's inertial reference frame. b. How long does...
  40. A

    Ray Tracing and Lens Formula for Image Location

    Homework Statement An object is locted 15cm infront of a convae lends with a focal length of 10cm. use ray tracing to determine the location of the image. try to draw to scale i)is the image upright or inverted? ii)is the image real or virtual? iii)use your ray-tracing diagram to...
  41. S

    Ray Tracing with Diverging and Converging Lenses: A Quick Guide

    If I have an object and in front of it there's a diverging lens, and in front of that (furthest from the object) there's a converging lens can I just ignore the diverging lens when ray tracing for the image formed by the converging lens? I figure if I were able to draw an infinite number of...
  42. J

    The rays of my ray diagram are not lining up

    Homework Statement I am given the object distance and height, and the focal length of the mirror and I must draw the ray diagram. Although this was drawn by a computer program that I programmed, I thought it would be more relevant in this forum, because I believe that the rays are correctly...
  43. E

    One question when we have a unpolarized ray and enters the polarized

    one question when we have a unpolarized ray and enters the polarized sheet it becomes polarized right , after that if i want to enter it to another polarized sheet with angle alpha with the y-axis there is a formula to find the intensity of the new light which is proportional to an angle I=I0...
  44. R

    Ray diagrams for mirror ray tracing

    Just a check here... I'm doing some ray diagram practice for optics and I've hit a road block. Hyperphysics is stating that for a concave mirror o is usually negative due to it measured against the direction of light propagation when applied to the mirror equation (below)...
  45. J

    Right Ray Topology: Excluded Set Topology

    Topology Excluded set << Original text of post restored by Mentors >>
  46. M

    Why does silver have lower absorption than zirconium at 35 keV?

    so just about finishing a report on x ray abosprtion on different materials, generally the linear attneuation coefficent increases with atominc number Z. However silver(47) had a lower attenuation coefficent then zirconium(40) despite having the significantly higher value of Z. With some...
  47. M

    X RAY ABSORPTION edge explination

    so just about finishing a report on x ray abosprtion on different materials, generally the linear attneuation coefficent increases with atominc number Z. However silver(47) had a lower attenuation coefficent then zirconium(40) despite having the significantly higher value of Z. With some...
  48. V

    Understanding Interference in Quantum Ray States

    A ray in Hilbert State is pure quantum state. All interference terms are supposed to be there. How does the interference work, between what basis vector, components or properties?
  49. L

    Project: Detect Gamma Rays with Cesium & Geiger Counter

    Hi, I need to make a project to demonstrate Gamma rays. I have cesium as a source to use and a geiger counter to detect gamma rays. Ideas are welcome!
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