Ray Definition and 493 Threads

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...

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?

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?

How does a CRT focus an electron beam? I get the basics of it. But I'm a little confused on the details. For electric focusing, how does accelerating the electrons cause it to focus? I'm looking for a more mathematical treatment of the subject. Everything I've found is just descriptive...

A Fe (57) atom is in an excited state 14.4 keV above the ground state. The nucleus decays to the ground state with the emission of a gamm ray. What's the recoil speed of the nucleus? I'm not sure how to set this up. I thought a photon would have no mass, therefor no momentum. If so I...

1. If a light ray go through a boundary of air and glass(i.e. angle of incidence is 90 degree), Is there any refraction or reflection? 2. If angle of incidence is 0 degree( the light ray is normal to a glass), Is there any reflection? 3. Suppose the situation is same as (2), but the light ray...

I was just thinking, nuclear fusion in the core of a star produces a gamma ray burst that takes about one million years to reach the surface of the star where it becomes visible light. Why does it take the gamma ray one million years to reach the surface if it is traveling at light speed? I...

Would a quark-gluon plasma reflect x rays and gamma rays and would such a plasma exist in gamma ray bursters and black holes?

What causes the short-lived, highly energetic, flash of light emitted by some black holes as they are created?

Hi...Juz curious. I was doing the prism experiment yesterday and was just curious about how the white ray of light changes to a spectrum of colours... Has it got anything to do with the change in the speed of the different colours of light, the frequency / the wavelength? Or just purely...

Thank-you for taking the time to read my problem. I am currently doing work with light and boundaries and have come across a question that I am having a hard time understanding. I know how to calculate angles when they go through one boundry but I can not figure out how to do it when there is 2...

Ok, a lens is held upright with a piece of clay. In front of it is a bulb, and behind it is a screen at the location of the image of the bulb. Now, what would happen to the image if the top half of the lens were covered by a mask? And what if the mask had a small hole in the center and were...

Hey guys In a few days i will be doing an Assessment task requiring me to do a number of things relating to experiments on Motors and Generators and Cathode Rays.. I am confident in doing all of it but the last part states we have to analyse secondary information to carry out a risk...

what kind of equipment do we need to detect cosmic rays? can i build something to detect fairly high energy cosmic rays in my basement?

{copyrighted material deleted by Phobos - please check out the link instead} Reference: http://www.sltrib.com/2004/Jan/01132004/utah/128616.asp

Does anyone know the peak(or the energy at which the flux is the greatest) of the GCR spectrum? And a quotable source for that. I am pretty sure it is in the 1-10 GeV/nucleon range. thanks

This Paper may be large, but it is a must for some pretty far reaching consequences for Cosmology. http://uk.arxiv.org/PS_cache/astro-ph/pdf/0312/0312347.pdf I will astounded if the paper is not seen in the near future as a remarkable paper of astronomical foresight and will be a paper...

It's embarassing to have to ask this, but I have never seen this issue discussed. Is there an upper limit on the energy of the gamma rays from the gamma ray bursts? Namely 1.022 MeV? Because any gamma ray of that energy or greater can and will produce pairs of electrons and positrons by...

Here is the problem: A glass sphere with a diameter of 5cm has a scratch on its surface. When the scratch is viewed through the glass from a position directly opposite, where is the virtual image of the scratch, and its magnification? The glass has an index of refraction n=1.50. Explain the...