Ray Definition and 517 Threads

Hello Guys! Please help me in this question: What is the nature of the gamma ray bursts? Why do they last for mo only 2 seconds? thx!

I am not sure if the universe ever expanded at speed inferior to that of light, but if it did, I am curious to know what would have happened (if it didn't happen) if a light ray (or any electromagnetic wave that is) had hit the boundary of the universe?

Homework Statement I have to find out a relationship between the deflection of an electron beam in a cathode ray tube and the accelerating voltage. Homework Equations I know that theoretically D is inversely proportional to the accelerating voltage. The Attempt at a Solution I have to...

Is there anybody out there that can help me?? Ok in a TV set, the electrons that are emitted come from the heating filament. Now as i read on this site...the heating filament replenishes its stock of electrons from an AC supply. I understand that bit. So there is an AC supply of electrons to...

Will all objects melt and burned if a high energy ray like gamma ray is shined unto it? My guess is no, since gamma photons will be absorbed by the objects if the photon energy is the same as the transition levels in the object. If it doesn't, then the photons will not be absorbed, and just...

When an electron and anti-electron come together a gamma ray is produced. So are gamma ray bursts just the product of lots of electrons and anti-electrons coming together? I gather that at least twice the mass of our Sun is required for a gamma ray burster to form,so if we have two masses and...

Hi! I know these cosmic ray flux rates on Earth: 10^{16} eV: the arrival rate is one particle per square meter per year. 10^{19} eV: the arrival rate is one particle per square kilometer per year. 10^{20} eV: the arrival rate is one particle per square kilometer per century. What are...

- the Flying Manta Ray :cool: :cool: :cool: http://www.youtube.com/watch?v=HBa9wdOANHw&mode=related&search=

Hey sum1 please tell me that : if d1=Ray of light through a glass slab(dotted line ie extension of unrefracted ray) and if d2=Refracted ray is d1/d2=mu(refractive index)

Why is the end of the hot filament where negatively charged electrons are being fired called the cathode end. 'cat' in chemistry means positive, I assume the same goes in physics as well?

Hi, I did a homework problem in which I was to show that a refracting telescope, modeled as a sequence of two thin lenses separated by a distance equal to the sum of their focal lengths, is capable of producing angular magnification. In my course we have been solving these questions in...

Homework Statement For an optical microscope, complete a ray diagram for an objective lens and relate the relate the relative distances to the lens equations. If you want to increase the magnification, should the objective lens have a shorted or longer focal length (illustrate this on the same...

Homework Statement The problem is: The left end of a long glass rod 10.0 cm in diameter, with an index of refraction 1.5, is ground and polished to a convex hemispherical surface with a radius of 5.0cm. An object in the form of an arrow 2.00mm tall, at right angles to the axis of the rod, is...

I'm hopelessly stuck on this question. Any help will be greatly appreciated. Prove that if we have a parabolic mirror with focus at F and axis of symmetry the x-axis, then a light ray emmited from F will be reflected parallel to the x-axis. To prove this consider the parabola y^2=4px (where...

Here is the problem I am working on: Sunlight enters a room at an angle of theta = 32° above the horizontal and reflects from a small mirror lying flat on the floor. The reflected light forms a spot on a wall that is d = 1.9 m behind the mirror, as shown in Figure 26-42. If you now place a...

HELP-HOMEWORK...Hi, I have homework that ask "Using the velocity of light find an approximate value for the amount of time that it takes a light ray to travel from the sun to the earth." Now I know the distance between the Earth and the sun is 93 million miles but I'm not catching on to the...

i need to find the expression for the vertical direction of a beam in a cathode ray tube, using: Va - accelerating voltage (between cathode &anode) Vd - deflecting voltage ly - effective length of deflecting plates L - distance from end of plates to the screen d...

For a course in Experimental Aerdynamics I have to study a section on Optical Measurement Techniques. My oral exam is coming up and there is this little thing I don't understand. It annoys me expremely. It is the ray equation. It is about light ray path in a medium with changing refractive...

hi all, may be my problem is a simple one. I want to calculate the intensity field resulted due to a UV lamp in side glss cylinder located at a distance from the lamp. The lamp is sorrunded 3 sides by reflectors such that 90% of the light power is reflected. now i have to calculate the...

Sir, Two plane mirrors M1 and M2 have a length of 2 meters each and are 10 cm apart. A ray of light is incident on one end of mirror M2 at an angle of 30 degrees. What is the number of reflections light undergoes before reaching the other end? I solved it in the following way: In each...

Pioneering physical chemist and physics Nobel laureate Ray Davis has died at his home in New York. Davis, who spent most of his career at the Brookhaven National Laboratory, shared the 2002 Nobel Prize for Physics for his contributions to neutrino astrophysics. He passed away on Wednesday aged...

hi, i have an exam on wave properties in a week. and i found this on the syllabus. i can't remember learning it let alone what a cathode ray oscilloscope is (an electron gun thingymajig?) my textbooks don't explain it well. so if you know how to determine the frequency of sound using a...

A converging lens has a focal length of 25cm. A 1.00cm tall object is placed 15.0cm in front of the lens. Find the image location and size, and describe it. Draw a ray diagram. Ok so I get 1/p + 1/q = 1/f rearranged for q=pf/p-f which equals -37.5, so the object is 37.5cm behind the lens. and...

An x-ray photon has a characteristic energy of 2.320keV. Determine its equivalent wavelenth in nm and the angle at which you would set a WD spectrometer containing an ADP dispersing crystal with an effective d spacing of 10.64A. I would appreciate any help on this question please, i don't...

is it possible to focus an axial ray through a double plano piece of glass placed in air? i don't think so because the glass will not reflect the ray towards the optical axis for the ray to focus in. is this thinking correct?

Hi guys! Question: A soft x ray source has an observed luminosity of 10^30W. The spectral shape indicates black body radiation with a peak in the emmision at 4KeV. Estimate the radius of the object. Suggest what source this might be. So, using L=sigma*A*T^4 and the peak energy is approx kT...

http://www.chicagotribune.com/news/nationworld/chi-0601180052jan18,1,1331355.story?coll=chi-newsnationworld-hed&ctrack=1&cset=true This makes me wonder. Is this guy losing it or what?

What is meant by a ray of light?

Last night I was watching a show on the science channel about astronomy. The show was very interesting but it was after my bed time and I fell asleep when they were talking about the mysterious origin of gamma ray burst. Last I remember they were talking about the burst coming from the early far...

Just a quick question here. On page 43 of this link http://www.physics.gla.ac.uk/Physics4/2004-5/P4H_SSPI_complete.pdf Why is the distance AP = k/|k|.r and similarly for OB :confused: :confused:

If we could produce the highest order of Gamma Ray energy of a single photon and bombarded an Atom with direct precision, Would the Atom be Annihilated? If the Atom is Annihilated then would the release of Energy of the Atom be greater than the Single High Energy Gamma Photon? Assume that...

Can someone please explain to me the difference between a cathode ray tube and a magnetron? I just started using a magnetron for sputter deposition in a project for a prof, and after reading about it, it seems to be the same. Just wondering, even though it may be a stupid question! Thanks!

Hello there, I've been working on the following question: A thin prism with a refraction index of n=1.41 has a top angle of 5.7 degrees. Find the angle of deflection for a light ray that falls on the prism surface : (a) normally (b) At an angle of 4 degrees I have worked out the second...

If IR rays at the appropriate frequency are passed through a vaporized sample of an alkane, will the vibrations induced be converted into thermal energy? If yes, then will the process take a substantial amount of time (on the order of seconds)?

I have a 3D polygon and a ray! Please tell me how can I know if they intersect together and how to find intersection point between them? :confused:

When a ray of light travels from an optically denser medium to a rarer one such that the angle of incidence equals the critical angle, then the refracted ray grazes the interface. Now, will the principle of reversibility of light work in this case? If yes, please explain.

http://arxiv.org/abs/astro-ph/0506520 Title: Dark Matter Annihilation: the origin of cosmic gamma-ray background at 1-20 MeV Authors: Kyungjin Ahn Eiichiro Komatsu Comments: 5 pages, 3 figurs; submitted to PRD, Rapid Communication The origin of the cosmic gamma-ray background at 1-20 MeV...

I've been searching the internet for a reasoanable explanation for the fenomenon and one observation of a GRB 8 billion light years from Earth tranformed 1.3 times the mass of the sun into gamma radiation and 16 days later they detected a new blue galaxy with stars already forming. Can someone...

in a CRT, the deflection on the screen is 2.4 cm when the accelerating voltage is 480 V and the deflecting voltage is 36 V. what deflection on the screen will you see if the accelerating voltage is 960 V (doubled) and the deflecting voltage is 18 V (halfed)? answer is 0.6 cm can anyone...

Just saw the Mythbuster's ep where they build a fresnel type reflector that focusses the sun's rays. There's a guy online who built a small version of it: http://www.solardeathray.com/about.html Now, there's two things weird about both the construction mechanisms here. 1] In both cases...

i heard some breaking news about a gamma ray emission which is confusing some scientists. did anyone heard about it?

After only recently learning about Cathode ray tubes at school i was taught that the striations caused in the tubes were the result of ionisation on the particles within the tube. Though this seems most correct i have also read in textbooks and been told by others a couple of other reasons for...

I'm having a lot of trouble drawing ray diagrams (this is for a lab assignment). If anyone could give me some tips or links to websites that are helpful in teaching how to draw ray diagrams that would be great. One example of a problem is: A 1-cm tall arrow (the object) is placed 2 cm to the...

Well, this Thursday, on my birthday, "Dr. Gene Ray, Wisest Human" will give a lecture on his Time Cube theory. If you have not heard of it, look here: http://www.timecube.com/ . If anyone can decipher what he is talking about, please share your thoughts with the rest of us and explain it...

What is the recoil energy (in eV) of a 57Co nucleus emitting a 14.4 keV gamma ray? If anyone knows the equation that I can use, thanks.

Hi i have a question about a lens,im not sure if this is the right place to ask but il ask anyways...please help I am really stuck! Question: An object is placed 24cm infront of a concave mirror of focal length 18cm. Where is the image formed and what is its magnification?Include an...

what is the use of AC-GND-DC switch?? wt will happen on the screen if a dry cell is connected to the CRO with AC-GND-DC button switched to AC?? then wt will happen if GND is on??

A ray of light strikes a mirror at an angle of 53 degrees to the normal. A) what is the angle of reflection? Ans: 53 degrees B) what is the angle between the incident ray and the reflected ray? Ans: 53+53 = 106 degrees C) A ray of light has an angle of incidence of 30 degres on a...

Its funny how one can forget how to do very simple things. :rolleyes: Here is a problem I've been working on and have a mental block and can't get the darn solution. It's from Krauss's EM text Note: Assume non-relativistic motion. I'm assuming beam enters between places with d/2 on each...

In a Cathode Ray Tube, the deflection on the screen is 2.4cm when the accelerating voltage is 480V, and the deflecting voltage is 36V. What deflection will you see on the screen if the accelerating voltage is 960V and the deflecting voltage is 18V?