Pair Definition and 379 Threads

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...

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...

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...

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...

hi I always heard my lecturer mentioned about 'less than 1 exciton'. as everybody knows, exciton is electron-hole pair. can we have <<<1 exciton? What does it mean? thanks in advance for your reply.

Homework Statement find all orderde pairs of integers (x,y) such that x^2+y^2=4x+2y Homework Equations The Attempt at a Solution rearrange to--> x^2=4x+2y-y^2 because x and y can only be integers, y(2-y) must be divisible by x so y(2-y)>=x y(2-y)=x(x-4) x(x-4)>=x x-4>=1 x>=5...

Pair of moving charges -- confused Here was a subject I thought I kind of had a grasp on, but apparently my understanding of SR is not very good at all! We have 2 charges, a positive and a negative one. I'm holding one in each hand, and I'm running forward, so their attraction is...

I'm trying to figure out what the transconductance of a bipolar differential pair with a certain tail current would be, but I'm getting tangled up in thinking like "well the pair sees half the input swing, but the transconductance might be double if there are two transistors.."etc. Could...

There were two piers reaching over the Thames. On each pier I spied a different friend of mine, fishing. These two friends were born of the same mother on the same day of the same year, yet they are not twins. How is that possible?

This question was brought to mind while reading other threads. I didn't think it was appropriate to diverge those threads off their subjects, so I started a new one. (hope this is right). I'm specifically thinking about the extremely rare event of the interaction of two gamma rays as the...

So, let's get this straight :smile:. Black hole evaporation is, by the layman's version, supposedly due to a negative mass particle entering the black hole, while it's counterpart leaves, as radiation. These particles are formed near the black hole by vacuum fluctuations (i.e. pair...

A two-dimensional harmonic oscillator is associated with the group Su(2). What is that association? Solutions to the Dirac equation require a pair of spinors at each point? Can we think think of spacetime as having pairs of 2D harmonic oscillators at each point? Thanks for any help.

Homework Statement I am given a one form Psi = zdx -xydy and two vectors v(1,1,-2) and w(-2,1,1) both tangent vectors of R3 at point P(2,-1,0). I am asked to find dPsi(v,w). Homework Equations Lie bracket? The Attempt at a Solution I know how to computer Psi(v) at p but this...

It seems to me that the Ginzburg-Landau equations are derived from considering the particle of superconduction to be behaving in a superfluid way. This required the particle of superconduction to be a boson so that B-E statistics might apply. The use of Bose's presumptions surely tell us that...

When a photon, with the help of a nucleus experiences pair production to make a positron and an electron, the energy of the photon will equal the rest mass of both the electron and positron together right? Then when the electron and positron annihilate, the two photons produces will each have...

Effect of a pair of slip rings in a DC motor Hi, I have a question here. Knowingly that the effect of a slip ring in a DC motor is to reverse the direction of the current in a loop whenever the commutator changes contact from 1 brush to another, so as to ensure the loop to be always...

Homework Statement As in the title Why can an electron - antiproton pair not be created by a photon in free space? This question came up last term but our tutor told us that it is because there are "no stimuli", I'm sure there is a better answer than this. I seem to recall that it can...

In Pair Production where a high energy photon collides with a nucleus a positron and an electron may result. But I have also come across references that say that two high energy photons can collide with each other to produce an electron and a positron. Is this correct?

Apologies if this has been asnswered before or if it's in the wrong place but I really don't know the proper terms I should be looking for. I have a system whereby people are asked to choose between two items, then another two, etc. until all paired combinations from the list of items has...

What holds a :smile::smile: pair together?

Why the decay of neutral pion to electron positon pair is forbidden?

I am trying to understand the cooper pair in a box. They don't seem to behave like normal particles. Can someone point me to a good intro. Especially on that focuses on how they are not like a quantum well. Some questions: 1) Does the cooper pair in the box see anything of the geometric shape...