Pair Definition and 400 Threads

Hi guys and gals, Here's a simple circuit mostly just an LED circuit with a Darlington pair. My question relates to the base current to the probe. If the probe is connected to an unearthed metal toaster (not plugged in), the LED glows briefly then goes out. If the probe is connected to the...

Homework Statement The minimum number of throws of a pair of dice so that the probability of getting the sum of the digits on the dice equal to 7 on atleast one throw is greater than 0.95, is n. Find n. Homework EquationsThe Attempt at a Solution There are 6 possible ways of getting a sum of...

There are exotic atoms such as the protonium (proton+antiproton) and positronium (electron+positron); I was wondering if quark-antiquark particles could appear even if they only exist for a fraction of a second.

can unhybridized atomic orbitals hold sigma bond electron pairs? To my knowledge, hybridized AOs can hold both lone pair e- as well as sigma bond e- pairs. But I'm not sure if unhybridized AOs can do the same. Thanks in advance!:smile::wink:

Is it true that static electric field 10^16 V/cm2 is capable to create positron-electron pairs? Is this process associated with energy release? If yes, where energy comes from?

I am trying to "perform" a thought experiment suggested in http://arxiv.org/ftp/quant-ph/papers/0206/0206190.pdf (Not that I personally have anything against non-locality :angel: Some of my best friends are non-local.) A source generates a single, narrow gated pulse of light containing one...

Okay so I have a problem with what my textbook is saying. It defined pair production as a process in which a photon of electromagnetic energy is converted to a pair of particles. But then it gave the discovery of an antiproton. Which was when a proton was accelerated to 6MeV and collided into...

Firstly apologies for not typing this out - but I need the diagram. And I have no idea where to start. I 'think' most of it is correct. BUT - I have no idea what to do with the last part of c. I thought I could just double the energy. But I'm going to get a negative energy for the system...

Find the resultant of each pair of forces acting on an object Q: forces of 6 N southwest and 8 N northwest I got 10 for the resultant, but how do I find the angle? The answer is apparently is 10 N, N82degW Having a hard time visualizing this...

If you consider the ##\chi_0 ## with a mass of ## 3.4 GeV/c^2## meson, why doesn't it decay to a pair of charged leptons? Technically it is possible though the weak interaction (Z boson) or EM interaction, right? Is it because it is so heavily suppressed because the strong interactions are...

Homework Statement My book repeatedly uses the phrase "contains one of each complementary pair of sets" and I am wondering what do they mean by that exactly? Homework Equations None The Attempt at a Solution For example, when it proves that an intersecting family of subsets of...

So i came to know that electrons residing across a tiny shell around fermi momentum takes part into the game of forming cooper pair but this phenomenon in real space is actually different. here all the electrons are taking part into this. what does it mean. i am not able to comprehend this...

I need to know how a pair spectrometer works but I can't find a book that explains it in detail. They say that it has three crystals located in a line and the beam is collimated on the central crystal and somehow this signal is only analyzed when there are simultaneous signals from the other two...

In one of my classes, I should give a talk about pair production cross section in front of the class and so I'm now searching for resources. But I can't find a place where the differential cross section for pair production process is given. Anyone knows somewhere I can find it and , preferably...

As far as I know a Baryon is made of three Quarks (eg uud, udd etc) and a Meson of two Quarks, a Quark/Antiquark pair. As I am not a student / scholar in Physics but very deeply interested in this field, I couldn't find any explanation, why a Meson is omly made up by a Quark/Antiquark pair. What...

Hello, In my problem I need to We are advised to create the Cooper pair box Hamiltonian in a matrix form in the charge basis for charge states from 0 to 5. Here is the Hamiltonian we are given H=E_C(n-n_g)^2 \left|n\right\rangle\left\langle...

Since I'm not sure if posting assignment questions is allowed, I'm just going to ask specific questions just to be safe. 1. Homework Statement Find all the lower bounds of given pair. Say (a, b) in T. Homework Equations Proof for greatest lower bound: ∀g,a,b ∈ T ⇔ ( g ≺ a) ^ (g ≺ b) ^ (...

Why there is no electron-positron production inside the, let say, Hydrogen atom?. I know that the electric field near nucleus get modified by some form factors making it not as big as the Coulomb field, but still i think is still very big.

I'm not a physicist, but I'm pathologically curious about such things. I've recently heard that there is a growing school of thought among theoretical physicists that the graviton (and resultant gravitational force) is actually just an extension of the strong force conveyed by a gluon pair. This...

Homework Statement One way of modeling tuples in set theory is through nested ordered pairs. A notation I'm not familiar with (I'm assuming it means that the following elements are nested into the last one) is used. (a1, a2, a2,... an) = (a1(a2, a3,..., an)). I have never seen the second "(" in...

Homework Statement The antiparticle of electron is positron, whose mass is the same as electrons, i.e. 9.1 * 10^{-31} kg but the charge is opposite. What is the minimum energy required to produce a electron-positron pair? 2. Homework Equations E = mc^2 The Attempt at a Solution Actually I...

Dark soliton is a general phynomenon in broad physics subjects. In higher dimensions, dark soliton exhibits instable except one special kind as vortex. The fundamental instability of a single dark soliton in two dimensions is to eventually decay into a number of quantized vortics through what is...

I am trying to read some of the experiments on entanglement. Is the pair of photons or electrons created by a laser hitting crystal? If this is so, then a pair of particles emerges? If this is also so, what is the big deal where the measurement occurs? The particles are created together at...

I just studied about the QM of singlet spin pairs. I have additional questions. Neither Wikipedia, nor past threads on this forum seem to address the questions. 1) A pair of electrons forming a singlet pair A. Can the pair be split again into non-entangled electrons? If yes how; just hit...

Hey! (Cool) According to my notes, each relation is a subset of an ordered pair. How can it be that each relation is a subset of an ordered pair, knowing that a relation is a set of ordered pairs? (Thinking)

An example:For m= 176 (132<176<172 one finds r=(3-2)x(5-2)x(7-2)x(11-1)x(13-2)=1650 relative primes (0<v<2x3x5x7x11x13), forming 825 asymmetric pairs, among them four partitions into prime numbers:19+157, 37+139, 67+109, 73+103, 79+97.

Nice to hear your comments...

Homework Statement Consider a box sitting on cart. When the cart is pulled with a force, P, the box A moves with the cart without slipping. In all questions, assume there is a negligible amount of drag. There is, however, kinetic friction between the cart and ground. What are the two sets of...

Hello Friends, I'm building a version of the leaky faucet experiment. Which is to say, I'm going to measure the period of water dripping out of a valve. To measure the event of the droplet falling I want to use an LED/IR pair. My understanding is that these things are basically like super...

Does pair production use helium nuclei for matter creation? Pair production occurs when a photon (Light Particle) strikes a heavy nucleus, it disintegrates and produces a pair of an electron and a positron. Is that heavy nucleus of Helium?

Hi, I am a little confused with the concept of action reaction pair of forces. Does this depend on mass? For example, if a train engine is pulling a buggy with force F, what would be the force applied by the buggy on the engine? The masses of the two are different and there is force of...

Homework Statement http://puu.sh/brbpb/3c7573fa32.png Homework Equations E = (mc^2 +K + mc^2 + K) P = E/c E = mc^2 The Attempt at a Solution The book says that the momentum/kinetic energy of the electron and positron produced in a pair production is so small that it can be...

Homework Statement An electric dipole consists of a pair of equal but opposite charges, +Q and -Q separated by a distance d. What is the electric potential at the point that's midway between these source charges? Through using the formula electric potential = kQ/r, I found the electric...

Hi all, I'm currently studying pair production by two photons (a high-energy one traveling in a isotropic field of low-energy ones), and I'm trying to understand the energy range of the electron created by this phenomenon. For this, I'm studying an old paper from Aharonian 1983...

I have a question regarding the calculation of the cross section in muon pair production from electron positron annihilation. After some calculations the textbook comes to the conclusion that the differential cross section is approximately equal to: (1+cos(theta)^2)alpha^2/(4*s) where alpha...

I was looking at some space-time diagrams with the simultaneity surfaces for moving inertial observers in SR and looking at the picture an interesting thought came up to my mind. It is known that the causal structure of the universe is preserved in SR, and that cause always comes before the...

Hi, is there a way to compute the escape velocity/kinetic energy of a newly created electron/positron pair ? Or in other words: How much excess energy (beyond 2 times electron mass) has to be put into the creation such that they will escape each other into infinity ? Thanks and cheers

I'm sorry, I wasn't exactly sure where to put this question but this section is probably my best bet. I'm basically trying to understand potential functions of more than 1 parameter... which is basically, most potential functions out there for molecular dynamics, what I just started working...

Why do I need a "processing" code when I pair Arduino with bluetooth I have a need to connect my [Arduino+Bluetooth dongle JY-MCU V1.02] to my laptop in-built bluetooth device.Most forums suggest using a processing code to go ahead and do this...

I wanted to try using a Darlington pair with an ion chamber (small tube) to detect alpha particles, as this site explains: http://www.techlib.com/science/ion.html Before I order any components, I was wanting to throw something together with some normal transistors I already have. I was...

Homework Statement The force between an ion pair is given by F=-k\alpha\frac{e^{2}}{r^{2}}[1-\left(\frac{r_{\circ}}{r}\right)^{m-1}] Find the value of r where the equilibrium position is. Determine the effective spring constant for small oscillations from the equilibrium. Using...

I don't completely understand why an electron positron pair cannot be created from an isolated photon. I understand it must have something to do with 4 momentum conservation, but I really can't see a problem given the photon has enough energy for the mass to energy vice versa conversion.\ The...

Homework Statement I need help rationalizing the following: a) Bond angle for H2S is only 92o whereas bond angle for H2O is 104.5o. b) If bond-pair<-> bond-pair repulsion is maximum for the C-H bonds in CH3X, ∑ all bond angles is 450o for CH3X c) For CH2Br2, the H-C-Br will be the smallest...

Hi, I've been reading about Feynman diagrams lately and I'm trying to understand the pair annihilation diagram. The picture's here: http://en.wikipedia.org/wiki/File:Feynman_EP_Annihilation.svg I don't understand the following things about the diagram: 1. Why anti-patricles have to...

A homework question is asking for a diagram illustrating a photon becoming a electron-positron pair (please don't post an image as it's homework). Looking through the internet there seems to be some disagreement as to whether a single photon can create an electron-positron pair: "Show that...

Hi, I'm a little confused about positronium. Accouring to this article http://www.answers.com/topic/positronium it states on the one hand that it is just an electron and a positron orbiting around their common center, held together by electro-magnetic forces due to their charge. On the...

Suppose in thought experiment one electron positron pair is annihilated in the carriage of fast moving train while the other pair is annihilated on the platform . Will the frequency of the photon reaching the platform from the carriage will be same as given out by the other pair which which is...

Hi there, My homework problem is on particle physics and asks me to draw a feynman diagram for pp→\bar{t} t interaction, which is what I think the LHC is planning to do (or possibly is doing). For the more traditional interaction; \bar{p} p→\bar{t} t I have this diagram; In this...

Homework Statement Find f(t) for the function F(s)=(10s^2+85s+95)/(s^2+6s+5) and apply the initial and final value theorems to each transform pairHomework Equations Initial value theorem: f(0)=lim s->∞ s(F(s)) Final value theorem: f(∞) = lim s->0 s(F(s))The Attempt at a Solution After dividing...

Homework Statement My book writes the following: using pair for the Discrete Time Fourier Transform: -a^{k}u[-k-1] <---(DTFT)---> \frac{1}{1-ae^{-iw}} for \left | a \right | > 1 Homework Equations Well, for the simple similar pair such as: a^{k}u[k] <---(DTFT)--->...