Pair Definition and 400 Threads

Homework Statement Two point charges of magnitude 4.79 nC and −1.11 nC are separated by 39.4 cm. The acceleration of gravity is 9.8 m/s^2 The Coulomb constant is 8.98755×10^9 N · m^2 /C^2. What is the potential energy of the pair of charges? Answer in units of V. Homework Equations...

hi, am i right in saying that for gamma rays of energies above 10MeV, the main interaction mechanism is pair production? and this is independent on energy? (or is it compton scattering for example?) thanks

Has anyone ever done an experiment with an entangled pair (say a pair of photons of opposite spin) where both are measured at the same time (or at least a time less than the separation, d, of the two particles divided by the speed of light, d/c)? Less than d/c and more than d/c seem to be...

Please teach me this: Can a real photon be destroyed to create a pair of massive particle-antiparticle?.It seem that if it can be,the conservation of energy-momentum is violalated? Thank you very much in advanced.

1. Problem Statement What is the wavelength of each of the two photons produced when a particle pair of a positron and electron accelerated at 25GeV collide? Can the net result of this annihilation be only ONE single photon? Why or why Not? Homework Equations Etotal(initial) =...

Homework Statement Comment on the electric field lines of a pair of finite parallel plates (a) between the plates and (b) near the edges of the plates. Homework Equations The Attempt at a Solution

When an electron in a semiconductor is excited to a higher state, an electron hole pair is created. How does this not violate charge conservation, a charge of +e turns into a net charge of 0? Thanks for the help

I'd like some informed opinion on the following scenario, which in a certain article forms the basis of a controversial claim. Suppose an entangled spin anti-correlated pair of particles are generated by some process. Particle A flies off along the +z direction, particle B along the -z...

Isn't it that in entangled electron pair, it's random which side will have up and down spin... the two sides should produce opposite spin but the order is random.. however I'm confused by the following statements: "Recall that when you measure an electron's spin in one direction you...

"A high-energy photon creates a pi+ pi- pair." ? Homework Statement "A high-energy photon creates a pi+ pi- pair. What is the minimal frequency of the photon?" (+ other side questions) Homework Equations E = hf E = mc² The Attempt at a Solution Well superficially it looks very easy...

Homework Statement "Prove that pair production is not possible in the absence of matter." Homework Equations / The Attempt at a Solution First of all, I'll assume a photon is considered matter, cause two photons can create a pair. Second: I thought pairs pop into and out of existence all the...

Hey all, Just like to prefix this question with the statement that I am a computer scientist with a strong interest and passion for physics, so please forgive me if this question is a tad naive. With that out of the way, I have a general question about this image: It's from "The Little...

Homework Statement Hi Its just me again! I kindly need help on this question. Its as follows: The tracks of a positron and an electron created by pair production in a magnetic field curve in opposite directions. a) Why do they curve in opposite directions b)Both particles spiral...

What does "to be opaque to pair production" mean? (I'm talking about fireball). I know what a pair production is but I can't get the crucial point: does it mean the photons don't collide? If it is so that means an opaque-to-p.p.- source have a greater luminosity (emits more photons) than a non...

Homework Statement Show that, if (x1, x2) is defined to be {{x1. {x1, y2}}, then (x1, x2) = (y1, y2) iff x1 = x2 and y1 = y2. This is from Willard's General Topology, problem 1C. I think Willard is trying to develop the set theoretic definition of the ordered pair, but this doesn't seem...

Homework Statement Find all ordered pair (x,y) of non negative integers satisfying a2 + 2ab + b2 = a + 4b Homework Equations none The Attempt at a Solution (a+b)2 = a + 4b or a(a-1) + b(b-4) + 2ab = 0 obviously (0,0) satisfies the equation. What about the rest? Please help!

Homework Statement Ok, I think i got it, but can you all tell me if these are the right/proper steps I must do? Determine the point of intersection of the following pair of lines: 3x - 7y = 8 2x + 4y = -12 Now, first step is the use the 2nd equation and turn the 2nd equation into...

Hi I have a small question in my mind about laws of forces. consider that we are hitting a ball with a bat. now again let's say we are in outer space.. so there is no Earth around... before bat hits the ball, bat exerts its gravitational force on the ball and as a reaction to this, ball...

Homework Statement Please find all ordered pairs of integers (x,y) such that x2 + 2x + 18 = y2Homework Equations x2 + 2x + 18 = y2The Attempt at a Solution Im not sure on how to begin. I tried square-rooting the expression, to solve for y, turning it into y = \sqrt{x + 2x + 18}. I would...

Homework Statement Prove the statement that (a,b) = (c,d) iff a = c and b = d with only using the first order logic (rules), the axiom of extensionality, the axiom of pair, and the definition that (a,b) = {{a},{a,b}}. Any intuitive approach should be avoided. The example of intuitive proof...

What is the probability of getting a 10 or a 11 when a pair of dice are rolled?

Homework Statement Electron and positron each have a kinetic energy of 220 keV even when far apart. Homework Equations The Attempt at a Solution I have no idea. My book says the answer 1.46 MeV, 8.49 x 10^-13 m but I don't know how to get that.

Homework Statement I need to calculate the differential cross section in order of Mandelstam variable t, instead of the angle \theta. My problem is with the change of variable not the amplitude of the process. I'm getting a global minus sign which can only be wrong. It seems I'm making a very...

I was trying a simple Darlington circuit with two Darlington-connected NPN transistors. There is an LED in the shorted collectors, connected to a 5V supply, and the base is open. The trivial objective was to see that when you touch two fingers to the base and the supply positive, the LED turns...

Hi all! I am learning superconductivity for the first time. As i saw, the supercurrent of some material is governed mainly by electron pair! Now my question raises here, how do those electron pairs form? What are their features compared to single electrons? Here is what i guess: "at very...

I'm a freshman in high school and was thinking of buying a beginner pair of binoculars. Could someone suggest one I might buy?

hey, i can't understand what is the motivation of defining pair of hole and electron as a single particle, exciton. thus they seem to have distinct motion and space. so why still we treat them as excitons?

Ok, so here's a question. The energy of say photons is frame-dependent. Photons are blue-shifted or red-shifted depending on my velocity towards or away from the source. However, what happens when I apply this to pair-production? For example, if my photons are energetic enough, they may create a...

Homework Statement If positron and electron have the same rest energy can pair production occur?Homework Equations E=hc/λ Plancks equation E=mc^2The Attempt at a Solution so i found the E of the photons using Plancks equation and found the photon E to be 6.83x10^-14 ( should I double this...

Hey Guys, Am working through Relativistic Quantum Mechanics: Wave equations by W.Greiner and have a simple question about the Klein-Gordon equation: is it fair to say that bound states only occur between -m<=E<=m? (c=1). There are a few problems where they show that you can get pair...

Hello, does anybody know how to compare (at tree level) the two reactions e^- + e^+ \to \gamma^\ast \to e^- + e^+ and e^- + e^+ \to Z^\ast \to \nu + \bar{\nu} \;\;\; \text{and} \;\;\; e^- + e^+ \to W^\ast \to \nu_e + \bar{\nu}_e The first process is the so-called Bhabha...

I have a small problem regarding darlington transistor pairs. Lets say a source is connected to the coupling capacitor Ci and this source has an internal resistance of for example 10kOhms. When finding the Output resistance of the darlington, should the internal resistance of the source be...

Hi! If I dissolve MgCl2 in distilled water, will it form into [Mg++] + [Cl-] + [-Cl] ? or [Mg++] + [Cl2--]? -And Why? is it because of stability constants? -Also Are there any intermediate steps in the process? Similarly, If I dissolve MgSO4 in distilled water, without electric currents or...

Let (xn) be a bounded sequence that diverges. Show that there is a pair of convergent subsequences (xnk) and (xmk), so that lim_{k\rightarrow\infty} \left|x_{nk} - x_{mk}\right| > 0

According to my textbook,inert pair effect has two definitions 1:-The occurence of oxidation state which is two units less than the group oxidation is called inert pair effect. 2:-The reluctance of s-electrons to take part in bond formation is called inert pair effect. But both the...

I'm planning on building a platform for Olympic weightlifting. I'm trying to minimize the weight, so I'd like to be able to properly estimate the sturdiness. The first one is for a piece of wood sitting on beams of some sort. I know that as the beams move father and farther apart, the board can...

Homework Statement A pair of oppositely charged, parallel plates are separated by a distance of 5.0 cm with a potential difference of 500 V between the plates. A proton is released from rest at the positive plate, and at the same time an electron is released at the negative plate. Neglect any...

I'm planning on building a platform for Olympic weightlifting. I'm trying to minimize the weight, so I'd like to be able to properly estimate the sturdiness. The first one is for a piece of wood sitting on beams of some sort. I know that as the beams move father and farther apart, the board...

In pair production, what is the formula for the energy of an electron or positron of this conversion. Also, what is the wavelength of a photon that can create an electron positron pair.

Homework Statement A bound quark-antiquark pair is a ________ while a bound quark triplet is a ________ Homework Equations The Attempt at a Solution I think that a bound quark-antiquark pair is a baryon while a bound quark triplet is a meson. Where can I find a mathematical...

Hi, I have a question which sounds like : Particle with spin 0 annihilates in two particles with spin one. What is the probability their spin polarization will in the same direction in short time? I think is 0 because of argument saving spin of the system and correlation function of two...

Homework Statement A long pair of wires conducts 20.2 (amps) od dc current to, and from, an instrument. The wires are 23mm apart, what is the magnetic field 9.7cm from their midpoint in their plane? Homework Equations B=(µo/2pi)*(I/d) The Attempt at a Solution µo = 4pix10^-7...

Why is the first transistor in the D-pair connected to one side of the load and not directly to the Vcc rail. As I understand, the purpose of the first transistor is to supply enough base current, so that the second transistor has adequate collector current to turn on the load. Fig here...

Homework Statement What is the uncertainty in the life time of an electron and positron produced in a vacuum?Homework Equations \Delta E\Delta t=\frac{\hbar}{2}The Attempt at a Solution \Delta E\approx1.6\times10^{-13}J \Delta t\geq\frac{\hbar}{2\Delta E}\approx 3ps (edited for Tex) This...

After an electron-positron pair is produced by a high-energy photon hitting the nucleus of an atom, is it possible for the produced positron to annihilate with a bound electron from the very same atom it was produced in? In this situation, what would happen to the produced electron--would it be...

In VSEPR theory, lone pairs repel each other more strongly than bonding pairs do, therefore they bend the molecule and determine its geometry. But why does that happen? What makes the repulsion stronger? Thanks for your help

The Kuratowski definition of the ordered pair is (a,b) = {{a},{a,b}}...this sort of lost me...how did they define an ordered pair (in which order of elements matters) using set notation (how does this definition work)?

One of the exercises in the text I'm using for self-study asks to prove that the union of a pair of atlases A and B on a manifold is another atlas. However, I don't see any way to show that two charts C,D in A\cup B with C\in A~,~D\in B are compatible. Could anyone give me a bit of help? Maybe...

Homework Statement Light of wavelength = 655 nm passes through a pair of slits that are 245 µm apart and travels to a screen 9.0 m away. How far from the center of the pattern is the third interference minimum? (in mm) d=245e-6 λ=655e-9 m=3 D=9 y=distance from center of 3rd...

Below is an excerpt from Quantum Enigma: Physics Encounters Consciousness. I have a few questions following the text. The text goes on to describe that by opening holes in the boxes, the wave function leaks out of both boxes and falls on a screen to which an atom will stick, resulting in...