Ray Definition and 493 Threads

Why in gamma ray emission there is no change in A or Z ? We know that in Alpha decay 2 protons and 2 neutrons are subtracted from the element. and in Beta decay there is change in atomic number by + or - 1. but why there is no any change in Gamma Decay in mass number A or atomic number. i...

Homework Statement The diagram shows a cube of glass. A ray of light, incident at the centre of a face of the cube, at an angle of incidence θ, goes on to meet another face at an angle of incidence of 50°, as shown in Figure 3. critical angle at the glass-air boundary = 45° Figure 3 (a)...

whats the highest frequency gamma ray normally emitted by any nucleus something that I read said that gamma rays were normally less than 10 Mev

I would like to build a cathode ray tube like this one: http://www.youtube.com/watch?v=XU8nMKkzbT8". It would be pretty damn cool playing with electrons. Do you know any references about this experiment? I mean, How could I build a glass vail and are there standard measures?

where can I get information about the excitation levels (gamma ray spectrum) of a single proton nucleus?

what type of ray does the bulb light emit?

In a 1964 publication Bruno Rossi describes an experiment where cosmic rays could penetrate dense materials. Finding that cosmic radiation at sea level could penetrate over 1m of lead. In these same experiments he was also surprised to record a higher rate of detection, as many as 35 per hour as...

Why couldn't Thompson just let one electron fly across the gap before disconnecting the battery and turning off the beam, and then measure the amount of charge deposited on the anode,thus allowing him to measure the charge of a single electron directly?

I am planning to use a gamma ray densitometer to measure the local concentration of slurry flow in a pipe loop. Since i am using an organic solvent(flammable) to make the slurry, i am worried that gamma ray passing through it will heat it up significantly and cause hazard. I would like to...

Can anyone explain Tesla's death ray to me in SIMPLEST terms? How did it work? what did it shoot? Was his design really accurate? And another thing, when people say it shot tungsten pellets, How big are the pellets?

Homework Statement A glass optical fibre of length L = 3.2 m is in a medium of glycerine with a refractive index n0 = 1.47 . The fibre has a core of refractive index, n1 = 1.58 and diameter, d = 100μm surrounded by a thin cladding of refractive index, n2 = 1.53. The end of the fibre is cut...

The almost simultaneous detection of low energy and high energy photons puts tight constraints on models predicting linear dependence of c on E. But it's very far from ruling out quadratic dependence. My question is, why do Lorentz-violating theories commonly predict linear rather than quadratic...

I just noticed that we tend to call EM wavelengths shorter than visible light "rays" while we call we call those that are longer "waves". Why is that? Did we ever think that "rays" and "waves" were physically different?

Hi guys, i have previously posted this question in the 'maths' section but had no reply, so i thought i would try my luck here. I'm having problems understanding the units of a cosmic ray flux graph. The cosmic ray flux is given in 'Counts/cm^2 s str', or the counts per cm squared, per...

Hello everyone, I am working on trying to model a bouncing light ray between two curves, and I would like to model it in Mathematica. However, I do not know what syntax or how to go about typing the code in. I tried to find examples on the Mathematica Documentation Centre but the examples...

I've been reading up on Gamma-Ray bursts, and one thing which has struck me is that, when described through light curves, no burst appears to be the same. Given the phenomenon seem to be based on standard principles, that doesn't make sense to me - behavior cannot be random. Is there any way to...

I know that intersection tests can typically (for hit detection in games) be computed in log n time with reasonable accuracy, but there is a problem that I see with using hierarchical bounding volumes in ray tracing. For example, a ray may intersect a bounding volume however due to the shape...

Hi I'm studying decay of atomic nucleus. Alpha and beta rays are essentially particles and their path are easily traced. But high frequency gamma rays easily penetrate metal foils, and I wonder that how gamma rays are practically detected and measured in lab experiments? Is photo-electric...

Homework Statement A young lady wants to see herself in a small mirror, the ear to ear width of her face is 6 in and eye to eye is 4 in. What should be the minimum width of a mirror so that she can see her face completelyHomework EquationsThere a few equations which when directly applied give...

I was wondering and have looked for a while on the internet to find out, in the end i found this site so i made an account. Can anyone tell me if light rays from stars fade out over time or if they travel for an infinite amount of time. Incase I am not clear enough, I am asking if light rays...

Why does a cathode ray tube (CRT) require a high voltage to operate?

I am having a hard time understanding the theory that a collapsed hypergiant forms a gamma ray pulsating black hole. Can someone explain how the em radiation can travel so fast with such energy as to not only escape the event horizon but also do so with such intensity?

Are there any known celestial bodies that at any time could collapse and produce a GRB directed towards earth? I know WR 104 used to be one, but they discovered it to be off at an angle.

For some of my work, I am investigating methods of scanning for nuclear material. As part of my study, I have run across Gamma Ray Spectroscopy: http://en.wikipedia.org/wiki/Gamma_spectroscopy" What I am having trouble with is reading a gamma ray spectrum (I am a software engineer with a...

Homework Statement The diagram shows a curved convex surface with radius of curvature R separating two media with differing refractive indices of n_{1} and n_{2} Show that the matrix representing refraction at this surface is...

Hi, Ive been readin about relativity, I am a little confused. The faster speed an object has, the faster time passes on the object. So how long does say a ray of light take to get from teh sun to the earth? It is ~8.5 of our minutes, but say I were on the ray of light; traveling with...

Can anyone brief of on the different rules for doing ray tracing for both concave and convex lenses, as well as both concave and convex mirrors?? I understand the concepts but i can't seem to keep ray tracing in my head from the way our textbook explains it...

I enjoy asking myself random questions and then finding the answers online i.e. forums however, I could not find the answer to this one. What would happen if a gamma ray burst hit a star or specifically our sun?

Homework Statement A 67-Zn nucleus is at rest and in its first excited state, 93.3 keV above the ground state. The nucleus then decays to the ground state with the emission of a gamma ray. (One atomic mass unit is 931.5 MeV/c2.) What is the recoil speed of the nucleus? (You can assume...

Homework Statement I can't understand my class notes nor wikipedia about this. It's very important to know how to construct the ray transfer matrix since it allows to solve many thick lenses problems. In wikipedia...

Homework Statement A sheet of plastic, n= 1.5, 25 mm thick is used in a bank teller's window. A ray of light strikes the sheet at an angle of 45 degrees. The ray leaves the sheet at 45 degrees, but at a different location. Use a ray diagram to find the distance between the ray that leaves and...

The question I'm confused about it below:- A unit cell of copper is cubic FCC. X ray data was measured at Lambda= 1.5406 angstroms. What is the volume? I think to find volume, I need to find lattice constant which is the length of the unit cell. The peaks were given and they are at...

When my Tv shoots electrons from the cathode ray tube , where do these electrons come from and is it ionizing whatever they come from.

Given the energy if sun were to instantly vaporize (using E = mc^2) = 2.7 x 10^47 J ( E = (mass of sun) * c^2) how far would one have to be from a gamma ray burst is order for the average power from it to be equivalent to the average power from the sun's radiation at the Earth (solar...

Given the energy if sun were to instantly vaporize (using E = mc^2) = 2.7 x 10^47 J ( E = (mass of sun) * c^2) how far would one have to be from a gamma ray burst in order for the average power from it to be equivalent to the average power from the sun's radiation at the Earth (solar...

Hi all, Got a bit of a problem with a lab experiment at uni (I'm not sure if this is the right place to post this, mods feel free to move it if necessary!) Anyway: We're trying to get a plot of efficiency against energy for a planar germanium detector. We've got spectra for different...

I have a 3D graphics book, which gives the formula for absorption of radiance along a ray. I am trying to derive the details and would like to see if my derivation is correct. Let o(p) be the probability density that light is absorbed per unit length at point p. They give the formula as...

Homework Statement I have a concave lens where f < do < R. I have to provide a ray tracing diagram. The Attempt at a Solution I drew the focal ray through the focus and parallel to the principal axis. I drew the principal ray parallel to the principal axis then through the focus. I...

I am looking for freeware which enable the simulation of a system with 3 mirrors, a laser, and a detector. So far I've only managed to find software for lenses on the internet. Would anyone lend a hand? :D

Homework Statement Paralel light rays travel from air to a glass hemisphere with radius R and index of refraction n_{g}that is greater than n_{air}. A top view is shown in the attached image. (a) Where do the rays focus relative to the point P? (b) The index of refraction of the...

Homework Statement A 2.0--cm tall object is placed in front of a mirror. A 1.0--cm tall upright image is formed behind the mirror, 165 cm from the object. What is the focal length of the mirror? Homework Equations The Attempt at a Solution I tried 37 cm, it was incorrect

Homework Statement An object is 12 cm in front of a concave mirror with a focal length of 21 cm . Locate the image in s' Is the image upright or inverted? Homework Equations willl get back with it The Attempt at a Solution Im not sure where to start, this should be a simple...

Homework Statement If the focal length of the concave lens is -7.50 cm, at what distance d_o from the lens should an object be placed so that its image is formed 3.70 cm from the lens? What is the magnification m produced by the concave lens described in above? Where should the object be...

Hello. I have a concern in relation to ray diagrams. So I read that the first incidence ray I draw must be parallel to the principle axis and be reflected such that it passes through the principle axis. Ok so this part isn't too much of a worry. However it states that the second ray must be...

Homework Statement I have done the light ray through a glass block experiment at different angles. I've taken the measurement for i1 which is from the incident ray. and i2 which is from the emergent ray. Then I have to take the average of i1 and i2 and then plot a graph using the average...

Is there a video of that kind of scenario floating around youtube? Have not had any luck finding a video of such a scenario.

Hi, For my experiment, i need the gamma ray energy spectrum of Cd-109 and Sn-113 with NaI detector. would anyone help me please? thanks everyone.

Hi guys I wonder if you can explain this to me. In http://en.wikipedia.org/wiki/Ray_transfer_matrix_analysis#Table_of_ray_transfer_matrices it says under "Thin lens" that the ray matrix is given by \left( {\begin{array}{*{20}c} {r_{final} } \\ {r_{final}^' } \\ \end{array}} \right) =...

Sorry if I sound crazy, but I just heard about this and would like a reliable fact check before I worry. So I recently heard about this binary star system known as WR104. I read that it was pointed right at us and, at some point in the future, it will release a gamma ray burst that will wipe...

I'm currently in the process of building a new muon detector using PMTs and Scintillators http://www.hardhack.org.au/scintillator_detector for testing the validity of my other cheaper detector projects. But I was also thinking of building another detector for logging average Cosmic Ray levels...