Ray Definition and 517 Threads

(Since this is a coursework question and not a homework question, I deleted the template) Both my chemistry and physics textbooks cite cathode rays as having the ability to excite or eject electrons from an atom (e.g., dielectric breakdown, x-ray spectroscopy). How can a stream of negatively...

Homework Statement The von Laue condition for x ray diffraction can be written dΔκ =2πn where d is a displacement vector between indentical atoms and n an integer What is the smalest angle θ through which x -rays of wavelength 0.12 nm may be scattered by a sample of polonium ,a simple cubic...

My interests are in astrophysics, so please forgive my ignorance of particle physics. I've just read Frank Close's book, "Neutrino"---excellent read, I'd recommend it---in which he points out that Ray Davis' first experiments to detect neutrinos from nuclear reactors (with no detections)...

The sun emits radiation in all directions. On the Earth, the rays from the sun are approximately parallel. Whatever side of the Earth is facing the sun at any given time is completely bathed in light. When I look at the sun, I can see it as an object..ie. my eyes can figure out where the rays...

I'm not even sure if it belongs in here... but my class is assigned to do this lab the objective is to determine that D=Vd/Va{(L1^2+2L1L2)/4d} is correct... so my teacher also want us to do 2 graphical analysis based on this formula I think i found one way of doing graphical analysis (if i...

Hi All, How can a high energy (above 1 MeV) gamma ray interact with a protium (hydrogen with only a proton in nucleus)? Does it only ionize it? Does it break it up? Does a chain reaction occur where antiparticles are formed and then annihilated, spitting out another gamma ray? I've been...

Dear Physics Forums, I am currently conducting an experiment on gamma ray coincidence from Co-60. Co-60 decays to an excited state, then de-excited by emitting two gamma rays. The aim is to deduce the angular momentum L of the first excited state. Apparently L indicates the type of...

Homework Statement A small bulb is placed in front of a convex lens. a) Suppose that the bulb is placed as shown. Using all three principal rays, draw an accurate ray diagram to determine the location of the image. Label the image location...

hello, my professer has been getting us to draw ray diagrams of two lens systems and diagrams of a lens and mirror system. these are two situations that i can not seem to figure out for my self two lens system : diverging lens to converging lens (pictures would be ideal)...

Homework Statement Have a few questions on CRT's. If we are given the accelerating voltage (250V) how would I calculate the kinetic energy of the electron as it leaves the positive end of the charge area? What is the formula for the speed of an electron along the tube (vz) as it leaves the...

Ray diagrams (lenses) urgent problem. I need full explanations. 1. The question An object of height 2cm is placed 15 cm from a thin converging lens of focal length 10cm. Complete the paths of two rays on the figure to show their passage through the lens to the image formed. 2. The...

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...

Homework Statement Consider free space (V (x) = 0 for all x). For the state function \psi(x, t = 0) = exp(ikx) + exp(i\varphi)exp(i2kx) where \varphi is some arbitrary real constant, determine (x, t) for t > 0, and (ii) the probability current density (as a function of x and t)...

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?

Homework Statement We have a parallel, transparent plate. The plate has an incidence of refraction that is dependent on a transverse coordinate. (i.e. the plate is perpendicular to z direction, and the refractive index changes along x direction) n(x) = 1.5/(1 - x/0.13) It is observed...

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...

Validation of relativity has been tested by measuring the apparent position of stars as our view passes by the edge of the sun. A difficulty being that we can not easily view stars with the sun so bright so we wait for an eclipse. I have a few questions: 1) Is this still a difficulty...

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...