What is Particle: Definition and 1000 Discussions

In the physical sciences, a particle (or corpuscule in older texts) is a small localized object to which can be ascribed several physical or chemical properties such as volume, density or mass. They vary greatly in size or quantity, from subatomic particles like the electron, to microscopic particles like atoms and molecules, to macroscopic particles like powders and other granular materials. Particles can also be used to create scientific models of even larger objects depending on their density, such as humans moving in a crowd or celestial bodies in motion.
The term 'particle' is rather general in meaning, and is refined as needed by various scientific fields. Anything that is composed of particles may be referred to as being particulate. However, the noun 'particulate' is most frequently used to refer to pollutants in the Earth's atmosphere, which are a suspension of unconnected particles, rather than a connected particle aggregation.

View More On Wikipedia.org
Recent contents Top users
  1. renec112

    Harmonic oscillator - chance of of finding particle x>0

    Homework Statement A particle is moving in a 1-dimensional harmonic osciallator with the hamiltion: ## H = \hbar \omega (a_+ a_- + \frac{1}{2})## at time ## t=0## the normalized wave function is given by ## \Psi(x,0) = \frac{1}{\sqrt{2}}(\psi_0(x) + i\psi_1(x)) ## Task: Calculate for ## t \geq...
  2. Alexanddros81

    Particle Motion; Acceleration directly proportional to time

    Homework Statement 11.10 The acceleration of a particle is directly proposional to the time t. At t = 0, the velocity of the particle is v = 16 in./s. Knowing that v = 15 in./s and that x = 20 in. when t = 1 s, determine the velocity, the position, and the total distance traveled when t = 7s...
  3. Alexanddros81

    Particle Motion: Zero Velocity and Distance Traveled at x=0

    Homework Statement 11.8 The motion of a particle is defined by the relation ##x=t^3 - 6t^2 - 36t - 40, where x and t are expressed in feet and seconds, respectively. Determine (a) when the velocity is zero, (b) the velocity, the acceleration, and the total distance traveled when x = 0...
  4. A

    Find the amount of work to move a particle from point A to B

    Homework Statement How much work should be done on a point charge of q=15 nC to bring it from infinity to a distance of 3 cm from a surface of a charged sphere? Diameter of sphere is 15 cm, its surface charge density is 12 microC/cm2 Homework Equations W=deltaU=q*deltaV v=kQ/r...
  5. Alexanddros81

    Motion of a particle and zero velocity

    Homework Statement 11.7 The motion of a particle is defined by the relation ##x = 2t^3 - 15t^2 + 24t + 4 where x is expressedin meters and t in seconds. Determine (a) when the velocity zero , (b) the position and the total distance traveled when the acceleration is zero Homework EquationsThe...
  6. Alexanddros81

    The motion of a particle is defined by the relation

    Homework Statement The motion of a particle is defined by the relation ##x = 6t^4 - 2t^3 - 12t^2 + 3t + 3##, where x and t are expressed in meters and seconds, respectively. Detrmine the time, the position, and the velocity when a = 0. Homework EquationsThe Attempt at a Solution [/B] Can...
  7. Fia Ismi Nur Alfiah

    Newtonian Mechanics : Rectillinear Motion of a Particle

    Homework Statement Find the velocity ± and the position x as functions of the time t for a particle of mass m, which starts from rest at x =0 and t =0, subject to the following force functions: (a) Fx = F0 + Ct (b) Fx = F0 sin Ct Ct (c) Fx = F0e^ct where F0 and c are positive constants...
  8. V

    Lagrangian for a particle in a bowl with parabolic curvature

    Homework Statement A particle of mass ##m## moves without slipping inside a bowl generated by the paraboloid of revolution ##z=b\rho^2,## where ##b## is a positive constant. Write the Lagrangian and Euler-Lagrange equation for this system. Homework Equations...
  9. B

    I For a particle on a sphere, is zero energy possible?

    In my introduction to quantum mechanics, I learned about the particle in a box, followed by the quantum harmonic oscillator. In both instances, zero energy was not possible; the ground states had non-zero energy. However, in deriving the solutions to the Schrödinger equation for a particle on a...
  10. A

    I Particle physics -- The collision of two Beta particles....

    I would likr to know what would happen if two beta particles were too collide with each other
  11. Mentz114

    I One particle and two slits

    The single photon experiment of Grangier showed that if a phase shift ##\theta## is introduced in one arm of a Mach-Zehnder interferometer then there is interference when the two beams are recombined - even if only one photon is introduced. If a particle encounters a double slit of suitable...
  12. S

    A Transformation of a scalar field

    I read somewhere that, suppose a scalar field Σ transforms as doublet under both SU(2)L and SU(2)R, its general rotation is δΣ = iεaRTaΣ - iεaLΣTa. where εaR and εaL are infinitesimal parameters, and Ta are SU(2) generators. I don't quite understand this. First, why does the first term have...
  13. D

    Energy analysis of a particle moving in a shrinking circle

    Homework Statement A particle of mass m is moving on a frictionless horizontal table and is attached to a massless string, whose other end passes through a hole in the table, where I am holding it. Initially the particle is moving in a circle of radius ##r_0## with angular velocity ##w_0##, but...
  14. Fia Ismi Nur Alfiah

    Mechanical Physics -- Find the velocity and acceleration of the particle from its position

    Homework Statement [/B] The position of a particle as a function of time is given by r(t) = i(1 - e^-kt ) + je^kt where k is a positive constant. Find the velocity and acceleration of the particle. Sketch its trajectory. Homework Equations v (t) = dr/dt a(t) = dv/dt The Attempt at a Solution...
  15. Allen_Wolf

    B Does Observing an Entangled Particle Affect Its Superposition?

    Consider two virtual entangled particles (+ve & -ve particles) which emerged out of nothing. We keep +ve and -ve in two different boxes. If the box containing +ve particle is closed and we do not observe the particle, then it is said to be in a superposition of +ve and -ve, Right? After some...
  16. J

    Graph of a particle in parabolic path

    Homework Statement Homework EquationsThe Attempt at a Solution I don't understand what is y-axis representing ? What is V(x) ? Is it potential energy ? Since the graph is a parabola , V(x) = kx2 I don't know how to proceed further .
  17. R

    Oscillation of a bound particle in a superposition of states

    Homework Statement A bound particle is in a superposition state: \psi(x)=a[\varphi_1(x)e^{-i\omega_1t}+\varphi_2(x)e^{-i\omega_2t}] Calculate <x> and show that the position oscillates. Homework Equations <x>=\int_{-\infty}^{\infty} \psi(x) x \psi^*(x) \mathrm{d}x The Attempt at a...
  18. F

    Direction of particle between two plates

    Homework Statement Homework Equations The Attempt at a Solution Since Fel > mg , the particle will move up with acceleration
  19. J

    Motion of a charged particle

    Homework Statement Homework EquationsThe Attempt at a Solution I am not quite understanding what is given in the question .Are the two directions of the fields known to us ? Assuming we know the two directions , say for example if we know that the two fields are in x and y directions , but...
  20. LonelyElectron

    Deriving an equation for the velocity of a particle

    Homework Statement Derive an equation for the velocity vx(t), vy(t) of the particle. - my teacher writes this oddly, that means the velocity in the x direction at any point in time, and the velocity in the y direction at any point in time. Calculate the initial velocity of the particle...
  21. AdrianHudson

    I Particle Focusing using EM fields

    Good day all! I have a question that has been in my head bouncing around for a while and I figured the best resource would be here as I can't find anymore related information (Or I am just looking in the incorrect spot). My apologies if this is in the wrong section I wasn't too sure where to...
  22. S

    I Weight of a relativistic particle

    If I were able to accelerate a particle to relativistic speeds, then capture that particle in a box in such a way that it kept its speed, then weighed that box, would it weigh more than the box + rest weight of the particle? Would it exert a gravitational field greater than that of the box with...
  23. M

    Question about charged particle in an electric field

    Question: A) A small charged sphere is attached to a thread and placed in an electric field. The other end of the thread is anchored so that the sphere is in a static situation when placed in the field. If the thread is horizontal, find the magnitude and direction of the electric field. The...
  24. T

    Mechanics II: Hamiltonian and Lagrangian of a relativistic free particle

    Homework Statement I am given the Hamiltonian of the relativistic free particle. H(q,p)=sqrt(p^2c^2+m^2c^4) Assume c=1 1: Find Ham-1 and Ham-2 for m=0 2: Show L(q,q(dot))=-msqrt(1-(q(dot))^2/c^2) 3: Consider m=0, what does it mean? Homework Equations Ham-1: q(dot)=dH/dp Ham-2: p(dot)=-dH/dq...
  25. H

    Particle accelerators and Casimir effect

    So I have read that particle that move near the speed of light can separate virtual particle for there anti-particle counter-part creating a new particle from the energy put in, but would this effect happen in particle accelerators like the large hadron collider, sorry if I am misinterpreting...
  26. F

    Harmonic Motion of a Charged Particle

    Homework Statement Two positive point charges Q are located at points (±l, 0). A particle with positive charge q and mass m is initially located midway between them and is then given a tiny kick. If it is constrained to move along the line joining the two charges Q, show that it undergoes...
  27. F

    I Exploring Oscillations & Interference in Particle Physics

    I will soon start with the course introduction to QFT and are hence an amateur on the subject. However I could not help but wonder, If particles are describes by oschlliations in a field, how can a "bigger body" be made up of several such oscillation? (A bigger particle is made out of several...
  28. F

    Abstract Special Relativity, particle at rest and one moving

    Homework Statement In frame S particle 1 is at rest and particle 2 is moving to the right with velocity u. Now consider a frame S 0 which, relative to S, is moving to the right with velocity v. Determine the value of v such that the two particles appear in S' to be approaching each other with...
  29. G

    Uncertainty for a particle diffracted through a single slit

    Homework Statement A horizontal beam of laser light of wavelength 486 nm passes through a narrow slit that has width 0.0590 mm . The intensity of the light is measured on a vertical screen that is 2.90 m from the slit. What is the minimum uncertainty in the vertical component of the momentum...
  30. J

    Conserved quantity for a particle in a homogeneous and static magnetic field

    The equation of motion for a charged particle with mass ##m## and charge ##q## in a static magnetic field is: ##\frac{d}{dt}[m{\dot{\vec{r}}}]=q\ \dot{\vec{r}}\times \vec{B}## From this, we can see that ##\frac{d}{dt}[m\dot{\vec{r}}-q \vec{r}\times \vec{B}]=0## and so the following quantity is...
  31. ohwilleke

    I Why do particle physicists use Gaussian error estimates?

    There is solid empirical evidence that error in particle physics measurements is not actually distributed in a Guassian manner. Why don't particle physicists routinely use student t error distributions with fat tails that fit the reality of errors in experimental measurement more accurately...
  32. Serra Nova

    B What does the Higgs particle consist of?

    The Higgs particle that were discovered in 2012 - what is it build of?
  33. Richie Smash

    Expected energy of a beta particle

    Homework Statement Nitrogen-17 emits a Beta particle to form an isotope of Oxygen. Use the following data to find the expected energy of the Beta particle. Mass of N-17 = 17.00845 u Mass of O-17 = 16.99913 u Mass of Beta particle = 0.00055 u Unified mass unit (u) = 1.66 x 10-27kg Speed of...
  34. M

    I Relativistic particle in non-uniform magnetic field (math)

    Hi everyone, I am currently working on a project in Physics analyzing the possibility of magnetic fields protecting against radiation particles such as fully ionized nuclei or electrons. I wrote a code in Matlab that simulates a 3-D magnetic field based on a combination of wires and wire loops...
  35. Javier Lopez

    What would be the capacitance of a particle on a plate?

    Homework Statement There is a charged particle at height h over a circular area of radii R, then I have to calculate the capacitance. This is useful when somebody want to calculate energy harvesting, antennas, sensors that measures ions in plasma devices and particle accelerators...
  36. O

    Force acting on superparamagnetic particle

    Hello, I'm currently doing the project and need to estimate the force that will act on the micron size superparamagnetic particle in the field of permanent magnet. I found several article there similar problem is solved, but I a bit confused. I hope someone could hep me. So, the main equation...
  37. B

    Calculate final velocity of electric particle

    Homework Statement A particle of mass 7.3 × 10−5 g and charge 24 mC moves in a region of space where the electric field is uniform and is 6.3 N/C in the x direction and zero in the y and z direction. If the initial velocity of the particle is given by vy = 4.1 × 105 m/s, vx = vz = 0, what is...
  38. pellman

    I 4-momentum of a massless particle

    The 4-momentum of a massless particle traveling in the z direction is (k, 0, 0, k). What is the significance of the value of k? It does not determine the speed since they always travel at light speed. If one particle has momentum (k, 0, 0, k) and another has (j, 0, 0, j) with j not equal to...
  39. T

    Potential of particle - why is there a scalar product here?

    I'm reading up on the Lagrangian equation, but what I'm asking is to do with electromagnetism. In the first equation here: http://www.phys.ufl.edu/~pjh/teaching/phy4605/notes/chargelagrangiannotes.pdf L equals the kinetic minus the potential energy. For the potential energy term, I just don't...
  40. Alexanddros81

    Two particle system - find their angular velocities

    Hi! I want to start solving problems from the text 'Orbital Mechanics for Engineering students' by Curtis 2nd edition. Is this the right place to post? Homework Statement 2.1 Two particles of identical mass m are acted on only by the gravitational force of one upon the other. If the distance d...
  41. F

    Which creates an electric field -- charge or a charged particle?

    wich creates an electric field charge or a charged particle (electron)
  42. W

    Motion of a particle from its momentum distribution

    Hi all, I recently learned the concept of Maxwell's speed distribution and became interested in how to use similar momentum distributions to study the probabilistic motion of a classical free particle. I have done some of my own reading on probabilities and distributions (no formal lessons yet)...
  43. D

    Intro Physics Photon and charged particle interactions with matter

    I am about to teach some of an introductory course for bachelor students in the field of medical physics. More specifically the topic "Photon and charged particle interactions with matter" in respect to radiation therapy (again, medical physics). I know there are a lot of topics within radiation...
  44. B

    B What is source of fundamental particle charge?

    Hello, Analogous to mass of fundamental (not composite) particles coming from interaction of those particles with the Higg's Field, does charge of fundamental particles come from interaction of those particles with some known/hypothesized fundamental field? Thank you!
  45. F

    I Two particle system, products and entanglement

    Hello everyone and happy new year. I have a quick dilemma on the concept of entanglement for a two-particle system and I am looking for some clarity: Say we have particle ##A## and particle ##B##. Both particles can be in either of the two states that we call ##|\Phi>## and ## |\beta>## or in...
  46. J

    Return time to its original state of a particle in the double infinite well

    Homework Statement First sorry for the traduction mistakes. Prove that any wave function of a particle in a 1 dimensional infinite double well of width a, returns to its original state in time T=4ma2/(πħ) . Homework Equations Ψ(x,t)=∑cnψn(x)·exp(-i·Ent/(ħ)) En=n2π2ħ2/(2ma2) The Attempt at a...
  47. T

    Understanding Random Particle Motion in a Monoatomic Gas

    We consider a monoatomic gas in a closed box. A textbook says : Since the assumption is that the particles move in random directions, the average value of velocity squared along each direction must be same. Why the assumption is that the particles move in random directions implies that the...
  48. M

    Engineering What can a nuclear engineer do in a particle accelerator ?

    Do they need a nuclear engineer in a Synchrotron ? if yes what kind of job does he do ?
  49. Pushoam

    Particle in a box quantum mechanics

    Homework Statement Homework EquationsThe Attempt at a Solution ## E \propto n^2 ## ## \frac { \Delta E} E = \frac { 2n +1} {n^2} ## In the limit of large quantum number, ## \frac { \Delta E} E = \frac { 2} {n} ##, option (a).
  50. Pushoam

    Force exerted by a particle in a box on the boundary

    Homework Statement Homework EquationsThe Attempt at a Solution The energy eigen - value of a particle in a box is given by ## E_n = \frac { n^2 h^2}{8mL^2} ## . Now, applying classical mechanics , ## \frac { p^2}{2m} = \frac { n^2 h^2}{8mL^2} ## . ## p \propto \frac { 1} L ## , So...
Back
Top