Ray Definition and 517 Threads

Finland's Slot Machine Association or RAY (Finnish: Raha-automaattiyhdistys) was a government-supervised and -owned nonprofit gaming (gambling) association (statutory corporation) in Finland. On January 1, 2017 RAY merged with the government-supervised and -owned nonprofit betting agency Veikkaus and Fintoto. The new company that was founded as a result is also called "Veikkaus". RAY was a gambling monopoly whose proceedings went to domestic charity such as pensioner care and gambling addiction treatment. While RAY was best known for its slot machines, the company also dealt in online gambling and controlled the only official casino in Finland, Casino Helsinki.RAY's operations were governed by legislation and decrees. The operations of the other Finnish gaming organisations, Veikkaus and Fintoto, are also based on the Finnish Lotteries Act. The act was last amended in 2012.RAY's revenue came from slot machines, casino games, and casino and digital gaming. All the proceeds from RAY's gaming operations were used to support Finnish health and welfare, and these funding decisions were also based on legislation.The history of the Tuplapotti predecessor, the Potti game, dates back to 1986, and in the 1990s a newer version of it was developed that rose to much greater popularity than its predecessor. The game was developed by Veikkaus (by then known as RAY), and the game is still one of the favorite gambling games in Finland.

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  1. A

    Linear attenuation coefficient for gamma ray attenuation

    Homework Statement I have data for the count rate (of gamma rays) against the thickness of various materials (Al, Pb, Fe etc...). I want to work out the linear attenuation coefficient. Can I do this by plotting the natural log of count rate against thickness? I don't have values for...
  2. G

    Gamma ray irradiation and a shielded chamber question

    Hi I was reading an article about a gamma ray materials testing camera built into one of the research reactors that worked in my country a while ago. Now I have a few questions regarding some of the issues the article wasn't informing about. It says that they built a special enclosed and...
  3. esha

    The validity of ray optics in telescopes

    the largest telescope in the world has an aperture of 10 m. According to the fresnel distance this makes ray optics valid for it, for a wavelength of lightsay 500 nm, uptil a distance of 2 * 10^7 m. I have read that after the fresnel distance, diffraction tends to dominate. But telescopes tend...
  4. Allen_Wolf

    Single Ray of Light: Visible from All Angles?

    IMAGINE an infinitely large space where there exists no particles or energy fields at all. If we introduce a single photon or a single ray of light, will it be visible from all angles?
  5. Ventrella

    A Find a circle inside of and tangent to a larger circle

    Start with a circle of radius r and center c. Inside of that circle is an arbitrary point p. Given an arbitrary normalized direction vector d, I need to find the radius and center the circle that (1) intersects p, (2) is tangent with the circle centered at c, and (3) has its center lying on the...
  6. W

    B Cosmic Rays Charge: Expect Reissner-Nordstrom Black Holes?

    Cosmic rays are overwhelmingly positively charged. Hence, whatever is emitting them must be building up an enormous negative charge. So should we expect to see highly charged Reissner-Nordstrom black holes out there? Perhaps even near extremality?
  7. T

    I Really parabolic light ray in an accelerated elevator?

    In an elevator "vertically" accelerated at g in outer space, the equivalence principle says a "horizontal" light ray in the elevator looks like a parabola. I completely understand that the light ray is curved but don't understand why the deflected light ray is an exactly parabola. Almost all...
  8. F

    I Propagation of a light ray : Multiply or not by factor

    I am working on a project which consists in calculating numerically the trajectory of a light ray in the Friedmann-Lemaitre metric with the case "k = 0" (euclidean space) and zero cosmological constant. The light ray is emitted by a source galaxy at instant ##t_{0}=\dfrac{2}{3H_{0}}## (today)...
  9. Adam Rabe

    Percentage transmittance gamma ray through lead

    Homework Statement Homework Equations I = Io e^-ux The Attempt at a Solution 0.75 = 1 * e^-u1 using algebra... u =2.117 I = 1 * e^-2.117*3 I = 0.00175 Answer is apparently 42.2. Can someone tell me where i went wrong? Thanks for any help as always
  10. dholbach

    Can a cathode ray tube be made from a light bulb?

    Light bulbs and cathode ray tubes are structurally similar in some respects. For example, both contain a filament -- in the light bulb, the filament heats up to produce light, while in a cathode ray tube, the filament emits electrons, which are then steered into a target (in a CRT TV, the...
  11. O

    Cathode ray tube, Voltage needed to move the beam impact spot

    Homework Statement Question: A cathode ray tube in a TV has an electron gun operating at 10 kV. a: What is the velocity (in m.s-1) at which the electrons are emitted? Answer:5.9x107 b: How many volts are needed between the deflector plates to move the beam impact spot across a 70 cm screen if...
  12. C

    Is the equivalent lens of two such that f_1+f_2<h divergent?

    The focal of the lens equivalent of two thin lens at distance h is $$1/f=1/f_1+1/f_2+h/(f_1 f_2)$$ Therefore, supposing that ##f_1>0## and ##f_2>0## (both lenses are convergent), if ##f_1+f_2 <h## then the equivalent lens should be divergent. Nevertheless consider the example in picture...
  13. C

    Ray diagram diverging lens both object and image virtual

    Homework Statement Draw the ray diagram of the case of a diverging lens where both object and image are virtual, that is ##f<0## , ##p<0## with ##p<f## Homework EquationsThe Attempt at a Solution I did not find this particular case of ray diagram in any textbook so I would like to know where...
  14. Spinnor

    Tracing a ray of light through a spiral phase plate

    Draw a single light ray through a spiral phase plate, anywhere but the middle of the plate, with the incoming ray being parallel to the axis of the spiral phase plate. On passing through the plate the ray is no longer parallel to the axis of the phase plate? Does the change in direction account...
  15. Daniel Petka

    B Energy of Gamma Ray Photon with Wavelength h

    What would be the energy (eV) of a gamma ray photon with the wavelength h (Planck's length)?
  16. P

    I Gamma ray cross sections from classical plane wave

    I am aware that in classical electrodynamics a metal exponentially attenuates TEM waves. I am wondering if this fact is sufficient to obtain estimates of the cross section of low energy gamma rays in metals. Obviously it would fail for higher energy gamma rays where Compton scattering and pair...
  17. R

    Energy of the photon emitted in a gamma ray decay

    Homework Statement An Fe nucleus (A=57) decays from an excited stated to the ground state by emitting a gamma ray. The energy of the photon is 14.4 KeV when the nucleus is held fixed. If the nucleus is free to recoil then the energy of the photon emitted will be? Homework Equations ## E =...
  18. Asamad

    Sun ray brightness quality after mirror reflection

    What is the Sun ray brightness quality after mirror reflection and what affects it? How to get the efficiency after reflection?
  19. P

    Is the Energy of Gamma Rays and Radio Waves Equivalent with Equal Amplitudes?

    According to the old thery of light the energy carried by by a wave is proportional to the amplitude of the electric field not to the frequency as Planck proposed, so an eletromagnetic radiation in the gamma spectrum carry the same energy as a radio one if their amplitude is the same? They only...
  20. J

    Optical Tweezers in the Ray Optics Regime

    Homework Statement Consider an optical tweezer operated in the ray optics regime as shown in Figure. Net reflection angle of the ray shown in Figure is θ = 10◦ (See Figure). Since more photons take the thick ray than the thin ray, a net force of F = 1 pN is exerted on the sphere toward the...
  21. T

    Approximating number of collisions in canal ray tube

    Homework Statement Canal rays, i.e., positive ion rays are generated in a gas discharge tube. How often does an ion (r= 0.05 nm) collide with an atom of the ideal filler gas(r= 0.1 nm) if it travels 1 m in a straight path through the discharge tube and if the pressure in the tube is 1 mbar? 1...
  22. F

    Chief Ray Angle and Field of View

    Hi all! I was studying the datasheet of a CMOS sensor when I bumped into a graph which defined the CRA (Chief Ray Angle) of a lens as function of the FoV (Field of View). cdn.sparkfun.com/datasheets/Dev/RaspberryPi/ov5647_full.pdf page 134 I've understood what is the CRA, and I've got the...
  23. P

    Ray gun from call of duty zombie?

    Can a ray gun be created? What would it fire? plasma? I know that the dimendion of the ray gun are too short for what am i going to say, but i want to ask if aside this problem this could work: I thought that maybe the things that you put in the ray gun to charge it are batteries, and that the...
  24. M

    B Is the Gamma Ray Burst Diameter Wide Enough to Engulf Our Solar System?

    Is it true gamma ray burst diameter can be as big as the solar system and the sky would become bright with its light even if it is 4000 light years away? Saw this at History Channel.
  25. Clara Chung

    How does a gamma ray get converted to visible light

    In the process of heat transfer from core to photosphere, each gamma ray in the Sun's core is converted during scattering into several million visible light photons before escaping into space.----from Wikipedia How does heat transfer related to scattering? Is it related to Raman scattering as...
  26. M

    I Velocity 4-Vector for Light Ray

    I hope I'm not violating Forum protocol, again. I tried posting this question in the Homework section but it got locked for violating homework protocol. My understanding for the relativistic transformation of a velocity u to u' is given by $$ \begin{bmatrix} \gamma_{u'} \\ \gamma_{u'} u'_x...
  27. Clara Chung

    B What is the recommended method to reduce gamma ray exposure?

    A gamma ray source emits gamma ray to a photographic plate in a container. The book said the blacked region on the photographic plate wouldn't be affected if the gas pressure of the container was increased. However, I think that the gamma ray will ionise more air molecules and lose more energy...
  28. Cocoleia

    Equation for the boundary of rays turning to plane waves

    Homework Statement I am given the following figure: These are converging rays that appear to be going to a point F convert to a plane wave upon hitting the boundary between n2 and n1, and I am asked to find the equation for the boundary between n1 and n2 that perfectly accomplishes this...
  29. Sebastiaan

    Using Gamma Ray reflector to reduce mass of Shadow shield

    Let's say we have manned space vessel powered by a highly power but radioactive rocket engine, producing a lot of deadly gamma rays. The classical answer to this problem is to use a shadow shield. However, Nuclear Shadow Shields are very heavy. What about the idea of instead of trying to absort...
  30. C

    Why don't we have gamma ray microscopes?

    Homework Statement Why? We can use shorter wavelengths than that of electrons to view electrons and more? What is stopping us? Can the image not be imprinted on a plate of some sort instead of being viewed by the eye directly? Homework Equations none The Attempt at a Solution I'm guessing no...
  31. CapnGranite

    Effects of a gamma ray burst on earth

    http://phys.org/news/2016-10-deadly-nearby-gamma-ray.html How deadly would a nearby gamma ray burst be? The original paper in Astrobiology is locked, but this summary is pretty complete. "A burst at the South Pole fits in with theories of the Ordovician extinction because the measured...
  32. O

    X ray crystallography - interpreting my graph

    Homework Statement I am currently part way through a laboratory experiment that utilises basic crystallography to ultimately calculate lattice constants and structure factors for NaCl (we receive formal training in the next academic year via full treatment of von Laue, Bragg diffraction etc). I...
  33. N

    Stargazing H.E.S.S. gamma ray telescope got an image of the moon

    https://en.m.wikipedia.org/wiki/File:Moon_egret.jpg Can we use better telescopes of this type (ground based gamma rays telescopes) to image the surface and subsurface of a planet with a lot of resolution?
  34. S

    I Can C60 Fullerenes Create a Freeze Ray?

    If a c60 fullerene was compressed below 70% of it's volume and accelerated at a target; reaching it before it decompresses, would it lower the temperature of the target on impact? If this was don't with a stream of fullerenes, could it be used like a freeze ray?
  35. Tareq Naushad

    When I lit a laser ray for 10 seconds from a distant planet

    I am on Alpha 4 light years away from earth. On 1st Jan, 2016 I lit a powerful laser light towards Earth for 10 seconds and then switched it off. My friend on Earth knows that he has to detect that light after 4 years on the night of 1st Jan, 2020 from a space station using a very powerful...
  36. SadPanda6022

    Why Do We Not Calculate Angle Change in Plastic Container?

    Homework Statement In this lab we used a half-circle container filled with water. Multiple angles are given to measure through the liquid in the container, calculating using snell's equation. However I don't understand why we do not have to calculate for the change in the angle from the plastic...
  37. EBPoncho

    PET/CT Gamma Ray Protection with Lead Apron

    I was informed I might get a better response by posting to this forum, so sorry for the double post. Hello all, I am currently attending a service course for a PET/CT system for my employer. We have been covering the physics behind the function of detectors and my instructor said something...
  38. A

    Cathode Coatings for Electron Emission: Investigating Materials and Techniques

    Homework Statement What 3 materials is the cathode coated with, from which the electron originate? Homework Equations None The Attempt at a Solution From what I managed to find, I think some may be nickel and barium but I'm not sure.
  39. Artlav

    Ray transformation of a 3d lens?

    Greetings. I'm working on a raytracer, and got stuck with trying to model a lens analytically. Given is a thin lens at position p with the axis n, radius r and a focal distance f, a ray hits it at position p1 going in the direction d. Which way would the ray be going on the other side of the...
  40. Chris Frisella

    EM Phenomenon: Magnetism from a Cathode Ray?

    I have recently studied about relativity being the reason for magnetism. The example given was about a magnetic field generated from current down a long wire. When two such wires with current in the same direction were parallel to each other there was an attractive force between them because...
  41. S

    Determining Gamma Ray energy from spectrum

    Homework Statement (Preface: I am not a physicist) The pulse height spectrum of a radioactive source known to emit high energy photons was measured using a small detector. Three distinct peaks were observed at heights of 7.38, 6.49 and 5.60 V, along with a continuous portion of the spectrum...
  42. Z

    For which incidence angle the ray won't come out of the prism's surface....

    Homework Statement A ray of light falls on the surface AC of a prism with a straight angle and with two sides equal. For which incidence angle the ray won't come out of the surface AB. The index of refraction for the prism is n=2. Homework Equations sina/sinb=n2/n1 The Attempt at a Solution...
  43. Eveflutter

    Help! Confused on Ray Diagram for Exam Question

    Fairly simple question I'd like someone to help with please. My teacher has me confused so I figured I'd turn to the forums for help. 1. Alright, so in an exam we had a ray diagram to draw. "Complete the ray diagram shown in Figure 6" they said (I sketched a replica * thumbs up*...
  44. prashant singh

    I Eratosthene's explanation of the sun's ray

    How can we say that when the sun is overhead then its ray will pass through the centre of the Earth , does it happens only at the one place on the earth. How they knew that synene is situated in the middle of north and south
  45. Developer_CM

    Gamma Ray Spectroscopy - 97 keV Peak for U238 Metal

    I recently acquired a 39 gram sample of U-238 metal. I ran a gamma spectrum on the sample and found a major peak around 97 keV. I couldn't find any documents that mentioned this peak for U-238, but it is very prominent. I ran a gamma ray spectrum on a 5 gram Uranium Oxide sample and it also...
  46. T

    Light ray deflected by the prism made of ruby

    i know snell's law is n1sin(theta)1 = n2sin(theta)2, and that sin(thetac) = (nair/n2)
  47. S

    Trace of cathode ray in changing magnetic field.

    I know that cathode rays follow a helical pattern if they enter a uniform magnetic field at an angle less than 90 degrees. This leaves me with two questions. 1. If the cathode ray described above, hit a phosphor coated screen, would it show only 1 spot or a circle? 2. If the magnetic field was...
  48. R

    B Cosmic Ray Muons: Finding Experimental Data for Special Relativity

    Hi everyone, I'm current working on a project about special relativity, and i was thinking writing about the cosmic ray muons. But where do i, as a high school student get raw data of cosmic ray muons? I have searched quite a bit, but it doesn't seems like data like that is public and easy...
  49. Jonathan Scott

    A Gamma ray burst associated with LIGO GW event

    Quite unexpectedly, it seems that the Fermi Gamma-ray Burst Monitor spotted what appears to be a hard gamma-ray burst about 0.4s after the LIGO GW event, lasting about 1s: http://arxiv.org/abs/1602.03920 This is not expected from a black hole merger (and as a black hole sceptic, I find it very...
  50. prashant singh

    What Happens When You Connect a 10,000 V Supply to a Normal Tube Light?

    suppose I connect a 10,000 v supply to a normal tube light. what will happen? will it behave like a cathode ray tube or something else
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