Particles Definition and 1000 Threads

Is there any centrifugal force acting on fine particles suspended in water inside centrifuge tubes? explain, not only by textual discussion

I have now seen it repeated multiple times that a particle (a fermion, perhaps?) moving in a condensate can exchange particles (bosons, most probably) "without effect" -- the version of this that I run into usually goes something like that the energy of the condensate does not change AT ALL...

Wikipedia says that virtual particles can not be observed, they are a handy concept for understanding what happens in quantum interactions, annihilating each other before they can be detected as real particles. However it also says that under certain circumstances, if they are moved apart from...

Hello, I heard that theoretical particles that have negative mass (techyons) are predicted to tend to speed up to infinite, if their energies are low enough. I don't understand why infinite speed instead of 2c (double the speed of light) are predicted? Note: I don't know whose/which theory it...

If electrons are fundamental particles and leptons then what happens when they emit or absorb photons or Z particles? What is known about the mechanism of these aborptions or emissions for any particles? Do the absorbed electrons gain mass as particles are described to do as they move nearer to...

Homework Statement Particle A and Particle B are held together with a compressed spring between them. When they are released, the spring pushes them apart, and they then fly off in opposite directions, free of the spring. The mass of A is 2.00 times the mass of B, and the energy stored in the...

Hello.This is probably totally stupid question, but anyway... Is it possible to create bag made of particles with very strong positive charge and electrons using attracting force between them? If theoretically at least in some parallel universe yes, then if we keep shooting electrons inside...

Whenever a charged particle is in motion ,there is both electric and magnetic fields created. Why is it that we only study one of it at a time ?

First I would like to say that I'm sorry if this question has been asked before- I'm new here. I was reading QED by Richard Feynman, and he mentioned that any given antiparticle is just it's regular particle counterpart moving backwards in time. How is this possible? I thought that it was only...

I do not know what area of the forum my question belongs in and I am not sure how to phrase it correctly so it will be understandable but I will do my best. At some point in time will the energy of all particles deteriorate to nothing (assuming an expanding universe) and if so how will it...

According to JJ Thomson's atomic model, Rutherford expected deflections of alpha particles through small angles. I'm unable to understand why he had expected "small angles". Can someone please explain.

Homework Statement [/B] Charged particles with equal mass and identical initial velocities move through regions of space that may have magnetic fields. Rank the magnetic field in each case from greatest to least. For this question, fields out of the page will have positive values, while fields...

I am having trouble making sense of the frequency of oscillations for a cyclotron. What I don't understand is, if a the voltage difference of the two dees is switched twice ( each time the particles are about to enter them), then why is the frequency of oscillation the same as the frequency at...

Hello everyone This is sort of a geometry problem. I'm sure it has an easy answer but it just won't come to me. Here's my problem A close packed colloidal aggregate of smaller spherical colloidal particles can be thought of as small spheres within a sphere. I have the relationship...

Why does the magnitude of a ket vector not matter? The motivation appears to be that a state vector only can decribe a particle, or no particle. But why shouldn't the magnitude of ket vectors not be used to represent the density of the particles, the average number of particles? I'm am fairly...

Hi everyone. Am trying to find out how many gravitons are in a quark, or in a proton. Anyone here know, or can point to a reference that might have the answer? Thanks!

Hi, I would like to calculate total number of particles in one periodic wave-section whose radius varies by h(z)=1+A*sin(2*pi*z/L), where A is the profile amplitude and L is the wavelength of one wave-section. I thought, I will do by volume integration, say integral over V (volume of one...

I'm wondering, I always hear how particles in the LHC collide with huge energies, and I'm wondering: how much energy is needed for particles to collide? I mean, if the energies in the LHC are huge and the ones in the RHIC are less huge you have to be able to do it with even less energy, right...

Homework Statement The first particle A is starting at origin and it has a velocity vector with magnitude 10km/h and moves at an angle of 30 degrees relative to y axis. The second particle B is starting at (0,5) and it has velocity vector with magnitude 8km/h and moves at an agle of 60 degrees...

Since particles have their own space i heard they cannot meet. But how about the origin if we see the axes perpendicular ?

Hello, I was wondering if someone could explain to me what does it meant that a beta particle has a range of energies ? Thanks

I was thinking about the connection between fields and particles. For instance the scalar field Φ(x) and the field Φ(x)+a both represent the same scalar particle. Because the action ∫∂Φ∂Φdx^4 is unaltered and the propagator <0|[Φ(x)+a,Φ(y)+a]|0> is presumably the same. What about if we replace...

Homework Statement I was given a task to model (using Matlab) 3 identical particles in external field and find spectra of lowest system energy states using gradient descend method for each particle in the system. I did a run of 500 random generated coordinates and found this distribution...

Hello and thanks for reading Homework Statement I'm in high school. I chose my yearly project in physics, and wanted to make a cloud chamber. The subject is "deflection of charged particles in a magnetic field", so I must set a magnet alongside the cloud chamber. I've prepared for it, bought...

When calculating the dynamics of a particle, we can use Feynman's path integral to determine the observables involved. This integrates over every possible path that the particle can take. We can even use it to calculate the vacuum energy of empty space. Now what happens to that vacuum energy...

Hi there, I am preparing to use the scotch tape method to get hex-Boron Nitride thin film from hBN powder. As far as I know, the available particle size for hBN is 10 um at most, is it possible for me to get hBN thin film using the peel off method with size larger than 10 um? If so, what is the...

Homework Statement A continuous cable of total length 4 m is wrapped around the small pulleys at A, B, C, D. If each spring is stretched 300 mm, determine the mass m of each block. Neglect the weight of the pulleys and cords. The springs are unstretched when d=2 m. The Attempt at a Solution I...

I am trying to figure out the difference between Δ0 and Δ- and the proton and neutron since both appear to have the same combinations of up/down quarks. Deltas have isospin 3/2 and spin angular momentum 3/2 whereas protons and neutrons have isospin 1/2 and spin angular momentum 1/2. I'm...

how light particles can penetrate through glass?

Here's a question I cannot seem to comply with my understanding of Quantum Mechanics. The characteristic wavelength of a particle is responsible for diffraction interference fringes, which is part of the wavefunction solution to the schrodinger equation. But the wavelength of a particle is...

We know that water waves are the simple harmonic motion of particles transferring their energy along the wave, but why do we say that water waves are not just particles, given their particle origin? Suppose then we say that a wave is just a collection of particles, then how do we explain the...

I understand why there is KE in the particles of a gas but I cannot really visualize the where the PE is coming from.. please straight forward answers!

Homework Statement I am stuck on this problem for my mechanics class. Please help me. Determine the force in each cable and the force F needed to hold the 4-kg lamp in the position shown. Hint: First analyze the equilibrium at B; then, using the result for the force in BC, analyze the...

Homework Statement Here is the problem that I am stuck on in my mechanics class. https://lh4.googleusercontent.com/ygXVjNfI4iP8xVpEjhxXZlWlDqg_VrM2gCVFLyomOVwWCfcLU78mIcPEc7hEzUqBoACIiQ=w1210-h506 Homework Equations F=-kx The Attempt at a Solution See the attached picture of my work...

I am trying to solve for the energy of 2 non-interacting identical particles in a 1D infinite potential well. I want to do it as much "from scratch" as possible, making sure I fully understand every step. H = -ħ2/2m * (∂2/∂x12 + ∂2/∂x22) Hψ=Eψ ∂2ψ/∂x12 + ∂2ψ/∂x22 = kψ, where k=-2mE/ħ2 I got...

Are there any elementary particles with zero intrinsic spin? Thanks in advance.

Homework Statement Consider Newton’s force law for two particles interact through a central force F12(r1',r2',u1,u2), where by Newton’s third law F12 = -F21. m1(d^2r1/dt^2) = F12(r1,r2,u1,u2) m2(d^2r2/dt^2) = F21(r1,r2,u1,u2) A. Show that Newtonian mechanics is form invariant with respect...

hello! what is the most efficient way to produce charged particles? like protons (H+) or electrons or ions or anything like that thanks!

Homework Statement Consider particles in a gas centrifuge. This device is used to separate gases of different molar mass by rotating a cylinder at high rates. Derive two equations: one for the pressure (P) and one for the particle number density (nv) as functions of M, r, w and T, where r is...

So our professor showed us wave patterns on a vibrating plate, by sprinkling powder over it. I'm curious as to why it behaved as it did.The powder moved to nodes, but I'm not sure why. I think it just gets bounced around until it lands on a node, which is stationary, so it then stays there. Is...

Homework Statement : Block B has acceleration of 4 m/s2... Relative acceleration of block A w/ respect to B is 4 m/s2. Find magnitude & direction of accel for A?[/B] Homework Equations a_A = a_B + a_A/B[/B]The Attempt at a Solution a_A = 4 +4 = 8 m/s2 <-- 8*cos(20) = 7.52 (x-component)...

1. Problem: Consider the composed system of two particles of spin ##s=1## where their angular momenta is ##l=0##. What values can the total spin take if they identical? What changes when they are distinguishable? The Attempt at a Solution : The problem I have here is incorporating the fact...

The below is what has me confused. It's essentially stating that if we apply a force on a positive charge and push it close to a negative charge, our applied work is negative. Why is this? I am confused about it because W = Fd and both F and d have the same direction. The potential energy U...

What is the evidence for dark matter being new particles as opposed to some modified form of gravity?

It looks to me like all the massless particles so far discovered may be force bearing particles, there being 3 of them. Am I right? If so can it be said that forces propagate at the speed of light whilst what we might think of a tangible particles cannot? I did post this question on another...

Homework Statement Two particles with spin ##S_1=1## and ##S_2=1## are in our system. For wavefunction of the first particle we know that ##S_{1z}|\psi _1>=\hbar |\psi _1>## while for the second particle ##S_{2x}|\psi _2>=\hbar |\psi _2>##. a) Find wavefunction ##|\psi _1>## in basis with...

1. In griffiths the following is written down in the chapter of identical particles: ##\Psi(\vec{r_{1}},\vec{r_{2}})=\pm \Psi(\vec{r_{2}},\vec{r_{2}})## Where it's + for bosons and - for fermions. However in class we have seen that for two electrons in the spin singlet situation the POSITION...

A thought experiment that is a consequense of a question someone asked in my particle physics class: We place an isolated electron. We wait 10 years, and place a half ring of electrons (spaced far apart from each other, but uniform) 10 LY away from our central e. Will our charges move? If so...

what is the correct understanding of a virtual particle? the popular science books would have us believe that a virtual particle magically pops up out of the woodwork, steals some energy and then puts it back before it ( the particl) disappears. Like a thieving employee who steal $100 out of the...

Hi All, I am in need to calculate the ultrasound (20MHz) absorption of particles (polystyrene of size 15 microns) in water. I tried to search in the internet, but couldn't find any simple analytical expressions. Can someone please help me ! Thanks in advance! Regards, Radel...