Rays Definition and 315 Threads

Hey all, I wake up with morning to find an email from spaceweather which says: EARTH-DIRECTED FLARE: Active sunspot 1401 erupted today, Jan. 19th, for more than an hour around 16:00 UT. The long-duration blast produced an M3-class solar flare and a CME that appears to be heading toward...

Well i couldnot help out with the concept that conventional tubes for x ray production require high acceleration voltages in the order of kVs but how a portable XRF produces x rays with a rechargeable battery ?? Does it produce high enough accelerationn pressure, i have some doubts or there is...

Are Alpha and Beta rays electromagnetic ? If yes, then how ? I would like to know how negatively charged beta ray comes from the nucleus ? Thanks !

1. Is there any clue as to how close two adjacent photons, coming from a distant star, in neighbouring paths, can be to each other? 2. Do their paths make a minute angle? or coming from a distance and heading towards earth, they are dead parallel to each other? 3. What, if the source of...

It is often said that the paths of light bend, close to a neutron star? What happens if the ray of light is vertical to the surface . If we take into account the spacetime of that inertial body, the constancy of velocity of light holds, (or does it?). But shall we (as outside observers) ever...

Radiation rays ionize the air and the same amount of negative and positive ions are generated during the ionization process. I would like to know more on how negative and positive ions are generated during the ionization process. Does anyone have any suggestions on what is going on during...

Homework Statement Given a cellphone layered with an anti reflection film with width L. A ray denoted with lambda hits the screen and some of the ray passes through while some of it reflects off from both inside the film and where the ray hits the film. The index of reflection from top to...

http://science.nasa.gov/science-news/science-at-nasa/2011/18oct_600mysteries/ "Fermi sees gamma rays coming from directions in the sky where there are no obvious objects likely to produce gamma rays," says David Thompson, Fermi Deputy Project Scientist from Goddard Space Flight Center...

http://www.bbc.co.uk/news/science-environment-15203788 Astronomers have spotted gamma ray emissions coming from the Crab Pulsar at far higher energies than expected. This challenges notions of how these powerful electromagnetic rays - like light, but far more energetic - are formed, researchers...

Canal rays experimental set up -- a doubt in this Homework Statement Please go through my attachment. It has been mentioned that luminous stream of particles were observed behind the cathode. Homework Equations Behind the cathode means , Whether right of the cathode or left of the...

Hi everybody, We know that light is an electromagnetic wave.gamma rays are e.m.waves. Both of them have the same speed 3*10^8 m/s. Gamma ray have the property to penetrate in materials like wood,cement wall etc. But,light is not penetrating even in a single wood. What is the reason behind...

Homework Statement 90% of the cosmic rays that fall on Earth are protons. So the outside of the Earth is hit by a net positive charge but does not seem to be, in particular, positively charged. How do you explain this? One last thing: I read that a body that is exposed to radiation becomes...

So apparently vacuum energy is created and destroyed within Planck time by matter, antimatter annihilation. If someone could theoretically stop or slow down time, would it be possible to tap into vacuum energy? Since annihilation creates gamma rays, I suppose vacuum energy would face the same...

In a discussion recently I came across the idea of an antimatter photon rocket, to quote http://en.wikipedia.org/wiki/Nuclear_photonic_rocket#Power_sources" Looking through various sites via google I've had a few answers as to how gamma rays may be reflected, the general consensus is that it...

Here are some recent papers on attempts to detect dark matter directly or indirectly: a solar system test with a possible positive result: http://arxiv.org/abs/1001.1697 direct detection, with seemingly contradictory results: http://arxiv.org/abs/1106.1066 via gamma-ray astronomy...

When the light enters calcite it is splitting in two rays perpendicular polarized to each other ordinary and extraordinary,right?But then which ray is perpendicular to the optic axis and which are parallel.I do not understand this because some books say ordinary wave is perpendicular and...

Homework Statement The directions state that you "must trace the light rays that would travel from A to B via refraction or reflection. Show what angle must be equal to what. Why does light take the path you charted Homework Equations The Attempt at a Solution I have provided...

I've seen quite a few videos in youtube (like http://www.youtube.com/watch?v=woiTedSKPrk&feature=relmfu ) and I wonder why we can easily see the laser in the air, as if there was some diffusion of it in the air.

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...

I am looking for a textbook that gives a good description of the cosmic rays hitting the Earth. Do you have any suggestion? Thanks.

Homework Statement This is a special relativity question: Two gamma rays of identical energies E collide with an angle \theta between their velocities. Show that positron-electron pair creation is impossible in the limiting case \theta=0. Find the minimum \theta value for p-e creation to...

Hello Guys, I have some questions relating to Cold Fusion / Low Energy Fusion. It seems Gamma Rays are not present from Cold Fusion experiments and Neutrons cannot be seen released from a sonar luminance reaction within the same nanosecond of time as the Alpha Process Completes...

I don’t have any more news. Do you? http://cdsweb.cern.ch/journal/CERNBulletin/2011/17/News%20Articles/1345733?ln=en It took physicists by surprise when analysis of the data collected by the two LHCf calorimeters in 2010 showed that high-energy cosmic rays don't interact with the...

I'm not sure if anyone knows, or if this really is a physics question, but I was wondering why bright lights always seem to have rays emanating from them. What I mean by this is that bright lights, such as the sun or a car's headlight, always seem to radiate light in visibly distinct bright...

I need to do a presentation to teach the rest of my class about Gamma rays. We need to do some sort of experiment to demonstrate Gamma Rays. Any ideas?

Can a faraday cage be used to stop the radiation at the Japanese reactor? If not why not? I know the frequencty is high but what if you pulsed DC current at the same frequency would that stop it?

It's known that light can have particles characteristic in a particular condition.

hi All, why is this? some matter has a refractive index of slightly less than one for light in the x ray region. This implies a phase velocity faster than c, right? could someone explain what is actually happening here? THANKS!

Homework Statement The problem is listed as follows: Show that conservation of energy and momentum require at least two gamma rays to e emitted in the annihilation of an electron by a positron. Homework Equations p(initial) = p(final) E(initial) = E(final) Total rest mass = 1.0218...

What would be the best protection from these two at the same time? Lead alone or a mixture of something like lead and Plexiglas?

Hello, I was reading the quote below in a safety debate and I had a question. It is generally accepted that flux density is not a safety issue, why is that? One would think that the more energy one fits into one place at a certain time, the more energetic the situation is. Like when you use a...

I read that gamma rays are usually emitted by the nucleus of an atom after it emits an alpha particle, but have been wondering: If the alpha particle being emitted was meant to stabilize the atom, and should have, why does the nucleus need to emit such high energy waves?

Homework Statement 2 parallel rays are traveling in a medium of refractive index 4/3. One of the rays passes through a parallel glass slab of thickness t and refractive index 3/2. What will be the path differnce between the two rays due to the glass slab? The Attempt at a Solution The...

Hey I recently did an experiment on the absorption of gamma rays I calculated the thickness and the no. of counts, got a nice exponential curve. So, I used lead as the absorbent or shielding material for gamma... Any suggestions what else I can use for gamma? I thought about sausages or...

Guys please help me with an answer to this question. Which substances can cosmic rays penetrate? I mean, can the cosmic rays penetrate stones, mountains, etc etc. Can they penetrate the human body also? If yes then the cosmic rays are bound to have influence on human bodies and minds? Kindly...

we all know the cosmic rays comes from outer surface of the Earth from higher altitudes and enter the Earth's atmosphere in all directions. but experimental studies have revealed that intensity of cosmic rays increases with altitude and reaches a maximum at about 20 km above Earth surface and...

i need a lens that will make the rays parallel to each other & focal point at infinite.without much loss in the intensity.collimator lens kind of action but not at the cost of intensity.

Alright, If you had a vacuum chamber and put in a gamma ray producing material (say Radium) would it produce plasma? I have seen someone do this with microwaves, so why wouldn't it work way gamma? Heres the site that uses microwaves to produce plasma...

Can someone tell me what are paraxial rays in brief. It would be better if there will be some diagram or visual!

Hey everyone, I know that this isn't quite the right place to post this but I will anyway. Does any Iron man fan out there know how his repulsor rays work? Are they plasma discharges from the arc reactor? Or is it an electrical weapon? Can anyone give me ideas or explain how they might work?

Here is a question I have for you. Is there a way to stop gamma rays through a dense material that is transparent? If so what is this transparent material? Can someone help?

Homework Statement An x-rays tube is connected to a 50 kV emf. Calculate the minimum wavelength that one can find in the radiation spectra that the tube produces.Homework Equations No idea! This is why I ask help here. The Attempt at a Solution Stuck at start. I've searched in google and...

What CAUSES alpha, beta and gamma rays?

Greetings, currently I'm working with cosmic rays (merely researching, not so much as working) and now I have a question regarding cosmic rays and cosmic rays detectors (specifically, Cherenkov detectors). How is the number of photons detected by the PMT's (photomultiplier tubes) related to...

Hello ,people I don't understand what is the use of Low Pressure and high voltage in cathode rays experiment and why do beams of electrons are produced under these conditions? Thanks in advance...

Hi all I don't know If this is the suitable section for this post.. but at all.. let's see if anybody can make me understand this :):) You all know of course J.J. Thomsons's three CRT experiments... The first one was aiming to prove that the appearing rays and the negative charges...

Is it to become a major problem as transitors get smaller & RAM amount goes up? A blog on NS said "This problem is projected to become a major limiter of computer reliability in the next decade." Will it be like moore's law with transistors size being a limitation? My comp has 4GB RAM &...

Lots of articles and papers I read talk about the gamma rays produced during fusion reactions. And yet, when I look at equations for fuel cycles, the sum of the energies of the fusion products equals the total energy liberated. Since this implies that all of the energy released in the fusion...

What happens to gamma rays as they travel outward from the core of the sun through the sun? -also, does it take a long time or short time for neutrinos to reach the photosphere of the sun from the core of the sun? Why? The main question has nothing to do with the earth, it is more...

Why can't energy is absorbed by protons rather than by electrons when a light ray strikes the atom.