Sources Definition and 517 Threads

Is it correct to assume that, in general, authors who have papers accepted by arXiv eventually try to get their work published in a journal? If so what should we make of arXiv papers which apparently do not get accepted by any journals? Should we take those papers as seriously as we would take a...

Homework Statement Imagine a interference pattern like the common water-wave interference pattern. What effect would decreasing the distance between the 2 wave sources have on the interference pattern? Homework EquationsThe Attempt at a Solution A change in the distance between the two...

Homework Statement I'm trying to find the voltage drop V1 of the following circuit, assuming Vin=1v, and for the life of me can't seem to get the right answer. Homework Equations KCL, Ohm's law The Attempt at a Solution I basically tried to use KCL at the top node, Vin/2+2V1 = V1/3 +...

1 - Huygens-Fresnel principle states that every point in a light wave is itself a wave source, 2 - light is made of photons, 3 - photons have a wavelength, they are QM objects. Hence my question : are photons the actual wave sources in Huygens-Fresnel principle ? Or are those two...

Homework Statement Four equally spaced coherent light sources (n=4) with a wavelength of 500nm are separated by a distance d = 0.1mm. The interference pattern is viewed on a screen at a distance of 1.4m. Find the positions of the principle interference maxima and compare their width with that...

Homework Statement I need to use mesh analysis to find the three currents: Homework EquationsThe Attempt at a Solution The answers are I1= -1.25A, I2=0.125A and I3 = 1.125A I don't know where I messed up for I3

Hi everyone, I wanted to know if any of you knows very good sources for quantum mechanics and spectroscopy fundamentals, like greats books, youtube videos (lectures), or any other option. I' m studying spectroscopy at the moment, and last year I've done the Physical Chemistry II course ( quantum...

It is well known that chromatic dispersion occurs when a white light source is incident on a prism. The index of refraction (of the prism) is greater for shorter wavelengths hence the colours emerge from the other side with an angular spread. However I am interested to know the detailed reason...

Homework Statement The following picture illustrate how the current in the circuit changes when you change ##E_2##. Where slope 1 represents the current flowing through ##E_1## and slope 2 represents the current flowing through ##E2## Homework Equations Usual circuit laws :P The Attempt at...

if you look up the cross section in Janis books, usually for same reaction, different cross sections are quoted by different laboratories. For example, the values of thermal neutron capture reaction 9Be(n, r)10Be: EAF-2010, 0.0075b ENDF/B-VII.1, 0.01b JEFF-3.1.2, 0.0088b JENDL-4.0, 0.0085b...

Hi, What is the scientific definition of "synchronous sources" when we talk about the conditions of interference? Thank you.

I have been thinking of this and can not seem to understand why nonlinear loads can be tought of harmonic current sources injecting current back into the grid? For example if you connect a passive filter in parallel to attenuate the 5th harmonic, the 5th harmonic would flow between the filter...

I appreciate the link to the field strength calculator. http://www.calctool.org/CALC/phys/electromagnetism/solenoid I'm also looking for recommendations on sources for magnets. What I'm trying to do is put together a Faraday Rotation Effect Lab. This is my Faraday Rotator, a 12 cm x 2.0 cm...

While I am sure that knowledge of quantum mechanics is vital for getting fission and fusion reactors to work, I can't help noticing that the actual function of those reactors can be described purely with classical physics. Are there any proposals for quantum reactions to unlock energy...

Homework Statement Solve this circuit: a) Mark all currents b) Write a system of equations allowing you to solve for the currents2. The attempt at a solution Part a) in attachment. Part b) \epsilon_1 = i_1 r_1 + (i_1 + i_2 + i_3) R \epsilon_2 = i_2 r_2 + (i_1 + i_2 + i_3) R \epsilon_3 =...

Assuming for now a simple photon particle model for light, where you have a stream of photons traveling with a certain frequency. Picturing this in my head on a number line, with just 3 photons at a time, and let's just say the wavelength is 1 and speed is 1, and at time t=0 we have a photon at...

Homework Statement a. Find the voltages Va, Vb, and Vc. b. Find the currents I1 and I2. Homework Equations Ohm's Law, Current Divider The Attempt at a Solution [/B] My first attempt was to redraw the circuit. I know that these voltages are with respect to ground. Therefore Va to Ground is...

Homework Statement The Question wants to find the Voltage Across The Current Source 2A and 5A Homework Equations KVL KCL Ohm's Law The Attempt at a Solution I tried to Using KVL and KCL for all Closed paths and node but I just Couldn't Figure how to relate them to find the voltage across the...

I've been very interested in analog computers lately, and a simple application of one has come up at work where I simply need to solve for RPM given a part diameter and feed (tangential) speed. It's simple enough to do the calculation in each instance, but I think it would be useful for the...

Hi guys. I need ur suggestion. Firstly, (I got to say that I'm new about this topic) I'm studying mechanical engineering and It's my first year. I've never learned about fluid mechanics or termodynamic or differantial equations before but I'm dealing with Aircrafts especially UAV. I've read...

Homework Statement Homework Equations The Attempt at a Solution this is my attempt, I figured this would be easier than typing. any how, I find partial fraction method is so time consuming and very algebraically complicated, is there a trick or another method I could use to make this...

Homework Statement Combining the current sources of the given circuit. I've attached the circuit diagram below. The Attempt at a Solution [/B] Since the sources are in parallel I can just add up the values to get an equivalent source and same for the resistors. I'm curious in the proof of...

Homework Statement https://session.masteringphysics.com/problemAsset/1383558/3/21.EX26.jpg Make a table with rows labeled P, Q, and R and columns labeled r1, r2, Δr, and C/D. Fill in the table for points P, Q, and R, giving the distances as multiples of λ and indicating, with a C or a D...

I'm interested in Killing vector fields and want to ask whether anybody can name me a good textbook or online-source about them, preferably with a general treatment with local coordinates as examples and not at the center of consideration.

Homework Statement Determine the vector potential due to a short wire running from (−L/2, 0, 0) to (L/2, 0, 0) carrying a current I = I0cos(ωt) (consider only points at distance r >> L from the origin). (You may neglect the effect of the return circuit.) Now determine the corresponding scalar...

Homework Statement :Find the current that go across the diode ans=0.86mA[/B] Homework Equations V=IR 3. The Attempt at a Solution The Vt(v total) is 30v so,must i ignore the diode as off first?.In that case the current is 30/20=1.5 mA. i also know the that diode is foward bias because...

What are your opinions about think tanks? 1.) Do you accept them as reputable, valid, and/or useful sources of political, social, and cultural commentary and analysis? 2.) Which think tanks do you find most reputable? 3.) Is there normally a bias associated with think tanks? Do...

Where can I find online primary sources for history?

Why will it happen so that-two light sources such that the ''phase difference between the two vibrating sources changes rapidly with time, we say that the two sources are incoherent and when this happens the intensities just add up '' assuming that the wave characteristics of light are significant

When an atom makes a single photon transition it adds a single photon to the radiation field. One might then expect that a low pressure gas discharge would emit photons in Fock states? How is it that photon of an atomic spectral line produced in a low pressure gas discharge become thermalized?

How are radiation sources like neutron or gamma/x-ray emitters used to detect materials? In particular illicit explosives and nuclear material and the such?

So I'm just doing a project where i have a electrically assisted bicycle and I am struggling working out the power when the bike is going uphill. If i have a certain force provided by the rider, and a force provided by an electrical motor; can I do Power=F_{motor}* v_{motor}+F_{rider}*v_{rider}...

Hi, i am halfway through one of my assignments and i require some assistance. I do not seek the answer to the assignment just a little boost to my knowledge. 1. Homework Statement Basically, if i am calculating the Thevenin's voltage and the resistor i have removed that is in question has a...

Homework Statement [/B] Homework EquationsThe Attempt at a Solution Applying KCL at the node , assuming current flows from left to right at the 4 ohm resistor: Vo/4 + 10 + 2Vo = 0 OR, is it : Vo/(4+6) + 10 + 2Vo = 0 since the two resistors are in series?

Hello there guys. As the title says, for quite some time now I've been looking for some extra sources of information. I am working with the book "introduction to electrodynamics" by David J Griffiths and even though it is good, I am thinking that it would be better to enrich my studies in this...

When I saw the report of a gamma ray burst associated with the LIGO GW event, my immediate thought was that the obvious explanation is that the compact massive objects were not in fact black holes, and the gamma ray burst was from the energy of the final collision and merger. This would...

Hi, I am trying to make one of my project plug into the wall. It needs 150 Watts, at 12 volts. I am going to use laptop chargers to power it, but I only have 2, 75 Watt chargers. Both of the chargers are 12 volt chargers, and I was wondering, could I use these two chargers in parallel to...

When you try to get fringes, the worse is when the source is extended and the light has a large energy spectrum. With a star, the source seems pointlike. Is there another advantage as regards with bandwidth?

Using the Delta Netowrk from this image: http://www.belden.com/images/B23_WyevsDelta.jpg Between Y-X, there should be 120V. Between Y-Z, there should be 120V. Between X-Z, there should be 120V. But wait! If we assign values to make the above statements true... Call X = 0V, and Y = 120V, so...

Hello all! I am a senior in high school with a love for physics. In English, we were assigned an argumentative research paper with a topic of our choice. So, naturally, I chose String Theory, since it is a semi controversial topic in theoretical physics today. My only problem is that I have a...

Homework Statement imgur link: http://i.imgur.com/G9RKEH1.png Homework EquationsThe Attempt at a Solution [/B] Should I just consider that A and B are parallel with each voltage source respectively and so therefore that's the voltage drop that they experience individually? The ground...

I have to find current Ix. Equations: None My approach: 1) Turn 60<0 and 2+4j impedances (top left of circuit) into current source parallel to impedances. 2+4j = 4.47<63.43 Current source = 60<0 / 4.47<63.43 = 13.423 < 296.57 2) The two impedances 2 +4j are now in parallel with the 6 ohms...

I am interested on the earliest reference on the deprecation of the concept of relativistic mass. AFAIR even Einstein used relativistic mass and the somehow related concepts of transversal and longitudinal force. I am trying to find a long lost article about showing all these concepts related...

Does anyone know the best online source(s) for kepler exoplanet data? Thank you.

Homework Statement In a flame test lab, where different unknown substances are heated and the identity of the substance is determined by the color emitted, what can be some sources of error? Homework Equations n/a The Attempt at a Solution I need three sources of error, and so far I have...

Greetings all, Are there resources around to help with writing essays for graduate applications? I have asked a few professors around my department, but as we don't have a graduate program and most of them are young professors who have only recently left grad school themselves, most of them...

Is anyone here involved in the search for new energy sources?

Any recommended books, published pieces, online articles, youtube videos to help understand (or at least introduce me) Quantum Physics? Hell, a college thesis would suffice.

Last year I tried Single Variable Calculus (very good course) and look some videos of Multivariable Calculus on MITOCW and I cover almost all the material. So, when I took that course I realized I want to learn about mathematics. I want to be a PhD physicist (and I know that it cover a lot of...

I know none of the source can perfectly be monochromatic. All that we can talk about is the degree of coherence. What I wanted to know is that suppose magically some how I get two independent perfect point sources of monochromatic light, then will then two independent sources be act as...