Ray Definition and 517 Threads

Why a ray of light passing through the centre of curvature of a concave mirror,gets reflected along the same path?

If I had a red laser light, will i be able to see this red beam in space?

I've been googling explanation for gamma ray bursts but couldn't find any that explain how and why the jets actually form, in one website I read that the jets have to be there to "carry off momentum and keep the black hole from spinning too fast", and no other details are mentioned in that...

The famous thought experiment that says that the path of light curves in a gravitational field uses the equivalence principle to demonstrate how, if you project a light beam through a hole in an elevator being accelerated through deep space, then to an observer inside the elevator, the path of...

How do CRTs work well and electrons can be sent to exact location on screen in CRT monitors if electrons can behave like wave? Is there something in old TVs (for example measurement device) along the road that electron travels to avoid behave like wave?

This may be a basic question but why does light ray bend in accelerating elevator but not in one with constant velocity. I know a frame of reference with constant velocity is indistinguishable from a stationary one from the inside but I feel like like somehow the light seems to know whether it's...

When you look up a ray diagram for a telescope you get the following: From reading my book it seems clear that the objective lens forms and image on the focal plane. This then serves as an image for the eyepiece. Since the focal length of the eyepiece at the focal length of the objective lens...

Is it possible for a light- ray to be redshifted to an extent where it no longer oscilliates and thus contains no information? Please excuse any naivety

What causes these striations? How does the voltage and pressure of the discharge affect the size, color, number, and spacing of the striations? I have produced a discharge with striations with fairly low voltage (under 15kv) and pressure 10 - 100pa, and the striations are very thin, compact, and...

Pair Production questions: 1) When a gamma ray photon pair produces an electron and a positron, do the two particles always have the opposite spin? That is, one always has +1/2(h-bar) spin and the other has -1/2(h-bar) spin? 2) Other than charge and spin, what are some other notable...

Homework Statement A cathode ray tube (CRT), consisting of an electron gun and a screen, is placed within a uniform constant magnetic field of magnitude B such that the magnetic field is parallel to the beam axis of the gun, as shown in figure...

In most (perhaps all) books it was mentioned that intersection of the light from the object when reflected by the mirror or refracted by a lens intersect at a particular point. That point when traced till the principal axis gives the image. (Provided object lies on the axis). I do not understand...

I have just learned about the cathode ray tube in the class room. There is a part called electron gun in it which emits electrons and these electrons finally strike the fluorescent screen.(I hope its correct till here.) But I want to ask that won't there be a loss of electrons in this process...

Hi, firstly I wanted to say thankyou for this forum, its provided me with a lot of help over the years and now it has come to that dreaded question that can not seem to poke at at all. I'm in my 4th year and taking General Relativity for the first time, with a hap-dash differential geometry...

Hi, I'm new in physics and optics so I need a little help. I've a simple optical system from 2 thin lenses. The first thin lens has a focal distance of 50 [mm] , and the second one has 25 [mm]. The 2 lenses are separated by 40 [mm] and the object is placed 75 [mm] before the first lens. I've to...

Alright I was doing some basic questions on ray optics when this doubt came to my mind So my doubt goes like this:(IT may be silly) Consider a concave mirror with pole P and centre of curvature C Its principal axis is extended on both sides Now consider a ray parallel to the principal axis Call...

Hi, I am searching for cosmic ray data (justfrom the sun), and am having a hard time finding data sets. Could someone give me a link or an idea to as where to look

I want to ask something about light, light can be defined as ray, wave, or particle. The group formed because of the wavelength, if the wavelength is less than the dimension of equipment it is grouped into ray, if the wavelength is equal to the dimension of equipment it is grouped into wave, and...

Today i woke up not so early around 8am, i get up and cooked breakfast and eat and had to drive for an hour to drop resume to get a job hehe..and went to a park for a walk to smell fresh air for about an half an hour. I get home about 1130am and i went to my basement to do some laundry, i put...

Homework Statement A solenoid is placed beneath a CRT that produces a magnetic field of 1.10 x -2. The CRT is 1 meter away from a screen. The electrons that make up the beam were accelerated from rest through a potential difference(V) at the beginning of the CRT. Acceleration of the electrons...

Hello, I am kindly asking for some help with following theoretical problem. Imagine at least two lasers emitting light at certain wavelength, each from different angle. Imagine that the rays cross at some point. Is is possible to observe at the crossing point light of different wavelength...

My question is, if X-Ray and Gamma rays overlap in the EMR spectrum, then how can they be classified differently. I have read about different energy levels but I'm just afraid I'm missing something is that the only difference?

Energy of beta ray and neutrino is equal Q=M(mass) of nucleous before-M of nucleous after,so it about 1Mev.But the mass of W boson is 80 MeV,so the least energy of electron and neutrino must be 80 MeV. Why there is the difference?Why does it seem that energy were not conservation?

Homework Statement http://i.imgur.com/q6EaspT.png 2. The attempt at a solution why is the answer C? shouldn't the aperture in front of the screen create a shadow that blocks all the light except the rays that go through slit? (the width of the slit is >>>1mm so it won't make a diffraction pattern.)

Today's APOD shows an animated visualization of a gamma ray flare detected by The Fermi Space Telescope. The video says, "each circle represents one gamma ray" That language suggests single photon detection. Is that correct?

For my year 12 physics EEI (extended experimental investigation) i need to develop some sort of experiment with variables i can change to retrieve data from. I have a basic cathode ray tube from a few months ago much like the one in this video: . Does anyone have any idea of what variables i...

Hey everybody, I'm right now trying to solve a question I found in a German physics competition 2006 concerning the diameter of a thin camera lens. I'm not able to find a solution, since there is basically nothing given. Here the task (I underlined phrases which might be important): A ruler...

Homework Statement i need to couple a ray (point source 15 deg) into a fiber with a small core diameter, the fiber located 8cm from the source. the focal distance of the lens is 1.5cm i need to choose 2 possible locations Homework EquationsThe Attempt at a Solution first suggestion: i placed...

The dinamic of a light ray in a Schwarzschild' s metric is governed by a lagrangian where the potential is V(x)= a*(1/r)^2-b*(1/r)^3 with a and b positive costants. The presence of a Lagrangian it means that is possible to apply a first quantization of this sistem; if so which are the...

Hi every one, What is the smooth gamma ray energy spectrum in gamma radiation? And, What is the algorithm of smooth gamma spectrum? Thank every one to much!

I'd like to write a computer program that simulates and visualizes the trajectory of a ray of light as it passes near a massive object (e.g., neutron star). In other words, I'd like to model light deflection in space. (FWIW, I have extensive programming experience, but my physics and...

On the Ultra-high-energy cosmic rays Wikipedia page there is an explanation that the 'effective' energy of cosmic rays differs from the actual(?) energy; and that 'only a small fraction is available for interaction'. How can that be, why isn't all energy 'effective'? "The energy of this...

Homework Statement Basically, derive the formula ## m = \frac{ 25 cm}{f_e} \frac{L}{f_o} ## using ray matrices. This just has variable tube length and assumes eye to object distance is 25 cm. Homework Equations Ray matrices: ## \left[ \begin{array}{cc} 1 & d \\ 0 & 1 \end{array} \right] ##...

Hello, Is this parameterization correct? - ##r(t) = R = \mbox{const}## ##\theta(t) = 0 = \mbox{const}## ##z(t) = ct## ##t = t## This is supposed to be the null geodesic curve in the case of a light ray, emitted at point {##r=R,\theta=0,z=0,t=0##} parallel to the ##z-##axis in flat spacetime...

Hello everybody, In one of my assignments I have lost a substanial portion of the grade for one problem because I haven't assumed that the energy of a Gamma ray = hf, I thought this was wrong, and that nothing in the statement says that it consists of only one photon. In fact, it says "high...

Hey guys first time poster. I have written a 2D ray tracer in Mathematica. It's very basic, all it does is use Snell's law to trace ray refraction and very basic absorption. The set up is a central absorbing circle surrounded by circular lenses. The central circle is a perfect absorber, so if a...

What happens to the brightness of a ray of white light as it passes through a prism?

This problem has been on my mind for a while. ---------- **Problem:** Show that **if** \begin{equation} |z_1+z_2+\dots+z_n| = |z_1| + |z_2| + \dots + |z_n| \end{equation} **then** $z_k/z_{\ell} \ge 0$ for any integers $k$ and $\ell$, $1 \leq k, \ell \leq n,$ for which $z_{\ell} \ne 0.$...

http://news.sciencemag.org/sites/default/files/styles/thumb_article_l/public/article_images/sn-gammarays.jpg?itok=vYTMw8My Researchers at Institut Laue–Langevin have found a way to bend gamma rays. Gamma ray lenses, which theory had suggested were impossible, could be made from heavy elements...

http://arxiv.org/pdf/1503.02320v1.pdf This paper discusses the emission of gamma rays from a neighboring dwarf galaxy. My understanding is that there is no conventional explanation of gamma ray emission. So there is interest in pursuing a possibility that these emissions are from dark matter...

I don't know a lot about classical physics but I was wondering how many volts a cathode ray tube emits?

Homework Statement In this lab various thicknesses of a few materials are placed between a source of gamma radiation and a couple different detectors. It is reasonable to assume that some small change in the thickness of the shielding would produce a proportional change in the intensity of the...

Homework Statement [/B] 1.) A muon is created by a cosmic ray interaction at an altitude of 60km. Imagine that after its creation, the muon hurtles downward at a speed of 0.998, as measure by a ground-based observer. After the muon’s “internal clock” registers 2.0μs , the muon decays? a.) If...

I have a question which has intrigued me for quite some time. If the electrons are accelerated using a potential difference in a cathode ray tube, the electrons should get accelerated till the time they reach the anode only. Once they cross over (ie. move to the other side of the anode), they...

I've heard of the muons and electrons that constantly hit Earth's surface in cosmic rays coming from extra terrestrial particles that break up in Earth's atmosphere but I was curious what factors played a role in the type of radiation produced from these particles in the atmosphere (i.e. More...

Hi, I am familiar with drawing rays through a lens. But when a few lenses are put together, things become confusing to me. For example, if a first positive thin lens at 0 forms a real image 10cm away, what would happen when we put a second positive thin lens, say at 5cm along the optical...

Homework Statement Hi please help me with these 2 ray diagrams... the questions is as stated in the attachment..i have no idea where to start drawing and whatever i have drawn is wrong for both qns.. thanks a lot experts! Homework EquationsThe Attempt at a Solution

Homework Statement I have to find the ray transfer matrix for a Plano convex lens, with a 5 cm radius and refraction index n=1.8. I'm supposed to use the paraxial approximation. Attached a homemade picture of the lens. Homework Equations Refraction at a curved surface: \begin{pmatrix} 1 & 0\\...

When people attempt to build one, they usually put objects near its focal point in front of the mirror but i wonder, has anybody tried "collecting" the light and aligning the beams in some way to be used as one? I know that the light is coming under different angles but is it possible to align...

If incoming light to a parabola is parallel to the central axis the light is reflected through the focal point and the back to its source. What about light coming in not parallel to the central axis. What path do these rays take?