Drift Definition and 168 Threads

  1. M

    B Direction of drift velocity vs direction of current

    I've done internet searches on this. There doesn't seem to be any agreement. Is the direction of the drift velocity in a wire the same as the (conventional) current? [AI Chatbot reference deleted by the Mentors]
  2. S

    Can London Basin drift east-west?

    Is London Basin fundamentally (by definition) capable of drifting east-west, or only north-south?
  3. M

    AC Drift Velocity: Understand Reactive Power & Movement of Electrons

    Hi All I hope this topic makes sense for this forum and somebody can help me to understand. This is what I understand (please allow numerical approximations): 1. Electrons move in a conductor at a speed anywhere near the speed of light. 2. Electrons gain actual velocity (drift) only when...
  4. J

    Find the drift speed of electrons in a wire

    We need to find each variable. ##I## is already given to us as 8 amps. The charge of an electron is 1.6 x 10^-19 coulombs. The cross sectional area will just be ##\pi(1.2∗10^−3)^2## m^2. Now we need to find the free electron density. We are given the density of of copper and can use dimensional...
  5. C

    A How Does the Ring Current Persist Despite Short-Lived Particle Drift?

    I read that "the azimuthal drift is compromized because the typical life expectancy of ring current particles is only hours to days and thus of the same order of magnitude as the drift period". But, if it is so, why relevant current exist? How could we armonize the fact that the azimuthal drift...
  6. F

    How Much Has Continental Drift Moved Your Hometown Over 750 Million Years?

    A California paleontologist has created an interactive map that allows people to see how far their hometowns have moved over 750 million years of continental drift. This is really cool! https://dinosaurpictures.org/ancient-earth#600
  7. r-swald

    Find the drift speed of of the electrons

    I've found I to be .167 using the potential and resistance. I also found the volume by multiplying the cross-sectional area by the length (?) and then dividing the # of conducting electrons into that to find packing density (n). To find drift speed, I would also need the area of the block as...
  8. jisbon

    Calculating electron drift velocity

    Just wanted to check in my workings to see if they are correct (seemed to be too short to me?) Since electrical conductivity is 820 (ohm.m) which is = n*e*(mobility) Mobility =0.17083? And I can simply get drift velocity by multiplying mobility with an electric field (600V/m)? Cheers
  9. F

    A Exploring the D0 Experiment: Proportional vs. Mini Drift Tubes

    Hi all, I'm reading an article describing the D0 experiment at Fermilab during Run II. Proportional drift tubes and mini drift tubes were used to detect muons: can someone explain me the difference between these two kinds of drift tubes? Thanks Federica
  10. somasimple

    Electrolysis and drift currents

    Hi, If there is an electrolysic in a vat, there is a positive and negative drift current betwwen the electrodes. Is it possible to have a situation where there is only one (either positive or negative) drift current? Thanks
  11. R

    Why Centrifugal Force in the Derivation of Curvature Drift

    Homework Statement This is a question about a pretty basic plasma physics derivation. In the standard derivation of the Curvature Drift of a charged particle in a magnetic field with curvature, the force that they use is the "imaginary" centrifugal force (or the force the guiding center sees in...
  12. nmsurobert

    I What is the Drift Rate of Jupiter's Great Red Spot?

    Can someone explain to me what "drift" is when talking about the rate at which the grs drifts around Jupiter? I have read several articles that talk about how the "drift rate" is changing. Is this the speed the spot is moving in the belt or zone it lays in? That is a different speed than the...
  13. S

    Coriolis Drift of Discrete Objects

    I am writing a program aimed at 'gun nuts' designed to display Coriolis Drift of bullets (ie, 'discrete objects in free-fall', and not large fluid masses). Using the 2 equations below, I am able to calculate and display the values of Coriolis Drift (in terms of X & Y (vertical and horizontal))...
  14. W

    How Can We Determine if Evolution is Driven by Selection or Genetic Drift?

    As I understand it , evolutionary change can be caused via selection effect or through genetic drift. are there any formal test for which is the dominant machismo for a given trait? A related question, is, we have lots of evidence that species evolve via nested hierarchy , but how can test if...
  15. W

    B Why don't man-made satellites drift away from the Earth?

    What is the difference between man-made satellites and the moon that causes the former to drift towards the Earth but the latter drift away?
  16. QuarkDecay

    A Velocity Drifts of proton-muon gas

    When do we use the equations of curvature drift ( ΔΒ⊥Β) V∇B= ±1/2u⊥rL (B x ∇B)/B2 and the general VF= c/q (F x B)/B2? For particles like muons and protons, do they need different equations to calculate a gas' drift velocity, when the gas is made of protons or muons instead of electrons? Am I...
  17. QuarkDecay

    Does Drift Velocity Change for Muon/Proton Gas?

    Homework Statement Cylinder electron gas with density of ne= 1010 and radius or r=1cm is inside magnetic field of B=104 Gauss. If we change the electron gas with (i) muon gas (ii) proton gas does the Drift Velocity change? Homework Equations [/B] Boltzmann equation of density...
  18. T

    I Calculating the curvature drift in a plasma

    How do i get this equation, $$\frac{db}{dl}=(\hat{B}.∇)\hat{b}$$ This equation is a vector whose direction is towards the centre of the circle which most closely approximates the magnetic field-line at a given point, and whose magnitude is the inverse of the radius of this circle. However I...
  19. N

    I Drift velocity in P-N Junctions

    When a P-N junction is in reverse bias, the drift velocity of the system increases, so why is there no current flow? Is the drift velocity not connected to the current? Thanks in advance.
  20. J

    B Physics of Drifting: Friction, Inertia & More

    Hello, I am making a project on the physics of drifting right now. I have searched the internet for a while now and have not found much about drifting. I am wondering how friction, the frictional force, the centripetal force, and how inertia impacts drifting. I am also wondering if there is...
  21. chandrahas

    Do force drifts occur in highly collisional plasmas

    I've read on wikipedia that the force drifts of the guiding centers off particles in a magnetic field also occurs in cold plasma. But does it occur in a cold plasma (Partially Ionized ) in which the mean free time is less than the gyro frequency time? I thought that the drift were present...
  22. S

    I The error bars of redshift drift

    Dear all, I am reading the paper "Cosmic dynamics in the era of Extremely Large Telescopes " by Liske et al. about redshift. I get the physical meaning of redshift drift, but when it comes to the error bars, I am confused. - Aren't the error bars given in equation (15) ? - Isn't this function...
  23. A

    What is the relationship between displacement, speed, and time in a random walk?

    http://imgur.com/a/hFubT http://imgur.com/a/fquuF In the first image, first line in the last paragraph. The first sentence define that carriers move with an average velocity component Vd in the x direction(in fact, carriers also move with an average velocity component in the y...
  24. T

    Genetic Drift Impact on Large & Small Populations

    Homework Statement Genetic drift play an imp role in: a. Large population b. Small population c.Bottleneck population d. Both b and c Homework Equations [/B] Genetic drift is the change change in the allelic frequency due to random sampling. 'Small populations are more susceptible to genetic...
  25. P

    I Deriving the E Cross B Drift Velocity: A Puzzling Explanation

    I am looking at this brief derivation of the E cross B drift for a plasma, starting at the top of page 3: http://www.physics.sfsu.edu/~lea/courses/grad/motion.PDF. I am a bit confused as to the justification that the drift velocity is perpendicular to the magnetic field, as stated at the top of...
  26. F

    How Fast Do Electrons Travel in a Copper Wire?

    Homework Statement A 5.00-A current runs through a 12 gauge copper wire (diameter 2.05mm) and through a light bulb. Copper has 8.5 x 1028 free electrons per cubic meter. c) At what see does a typical electron pass by any given point in the wire? Homework Equations J = nqvd The Attempt at a...
  27. R

    Charge carrier drift velocity of wire

    Homework Statement Homework EquationsThe Attempt at a Solution Current is I = nqvA so drift velocity V is: V = I/nqA Drift velocity for x is: Vx = I/nqA Drift velocity for y is: Vy = 2I/nqA So the ratio of Vx : Vy should be 2:1 since Vy is equal to 2 lots of Vx?? (but correct answer is B)
  28. G

    Why an electron's drift velocity is so slow?

    Electrons are moving VERY fast. However, they don't have a high drift velocity in a circuit. Why? Is it because every time they advance a little bit they collide with an atom? Or is it because the electric field in a circuit is not strong enough so the electrons don't get pushed enough?
  29. O

    Finding the drift speed of a conduction electrons

    Homework Statement The figure shows wire section 1 of diameter 4R and wire section 2 of diameter 2R, connected by a tapered section. The wire is copper and carries a current. Assume that the current is uniformly distributed across any cross-sectional area through the wire's width. The electric...
  30. stephen8686

    E-Field Through Copper Wire given drift velocity

    Homework Statement If the magnitude of the drift velocity of free electrons in a copper wire is 7.84×10-4 m/s, what is the electric field in the conductor? (Also gives chart that states that the resistivity of Cu is 1.7×10-8 Ωm) Homework Equations [/B] vd=(qEτ)/me (where τ is avg. time...
  31. moenste

    Find drift velocity of the current carriers in the copper strip

    Homework Statement ABCD is a plane rectangular strip of conducting material of uniform thickness, with a steady current flowing uniformly from AD to BC. The potential difference between E and F, the mid-points respectively of AB and CD, is zero, but when a magnetic field is set up at right...
  32. T

    Maximum current carrying capacity (theoretically infinite?)

    I started simply looking at a circuit breaker connection diagram, then I fell down the rabbit hole. So I wondered, if you had a piece of pure copper and getting rid of heat (structural integrity, gravity etc.) was not an issue, just how much current could you push through it before it hit it's...
  33. S

    Show the drift velocity is ExB/B^2

    A charged particle drifts in uniform, constant magnetic and electric fields. The electric field, E, is perpendicular to the magnetic field, B. Show that the drift velocity is given by vd = (E×B)/B2 Heres where I get to: F=e(E+vxB)=0 as v is uniform.Therefore E+vxB=0. Take vector product of B...
  34. Hyo X

    Reduce Amplifier Drift when load is near input impedance

    I built a voltage amplifier based on the AD625 instrumentation amplifier. This chip has a 1 G-Ohm input impedance. When the load has a resistance of 100 kOhm, output drift is negligible. When the load has a resistance of 100 MOhm, output drift is significant and not acceptable. Are there any...
  35. M

    Finding the electron drift speed

    Homework Statement A piece of n-type germanium is 2.0mm wide and 0.25 mm thick. At a certain temperature, the number of conduction electrons per cubic metre is 6 x 1020 m-3. What is the average drift speed of the electrons when a current of 1.5 mA flows? (e=1.6 x 10-19 Homework Equations...
  36. M

    How can an increase in area cause a decrease in drift speed?

    Homework Statement We have: I=nAve Imagine a copper wire with a constant current through it: I=constant e=constant n (for copper)=constant Hence, we obtain: A is inversely proportional to electron drift velocity. My question is: how does that make sense? Why would the cross sectional area...
  37. O

    Calculating Electric Field from Electron Drift and Diffusion in Si Sample"

    Homework Statement A sample of Si, in which 0<=x<=(25*10^-4), electron concentration is n(x)=5*10^16 cm^-3) * exp(-x^3/2*10^-8), temperature is 300k and electron mobility is 1300 cm^2/V*s. The electron current through the Si has both drift and diffusion components and total electron current...
  38. A

    Why is the E cross B drift velocity constant in charged particle motion?

    Homework Statement good afternoon, I am a problem with the E cross B drift velocity calculus from a charged particle. At first, an eletron is submitted a uniform magnetic field and have a circular trajetory. After, appear a uniform eletric field that create a drift velocity. The equations...
  39. A

    Average Electron Drift Distance with AC Current

    Homework Statement A metal wire with 1023 free electrons per cubic centimeter is carrying 60 Hz alternating current with a maximum current density of 100 amps/cm2. a) Write an expression for the average electron drift velocity as a function of time (vd as a function of time). b) What is the...
  40. person_random_normal

    Drift Speed of Electrons in Conductor with Applied Field

    for an electron, randomly moving inside a conductor , having applied an external electric field we have those electrons moving with a net speed called drift speed , against the direction of field. so initially as electrons are moving randomly we consider their initial velocity o and after time t...
  41. Priyank

    Exploring the Drift Speed of Electrons in Conductors

    Homework Statement :[/B] When a steady current flows through a conductor, the electrons in it move with a certain average 'drift speed'. The drift speed of electrons for a typical copper wire is about 1 mm s-1 . How is it then that an electric bulb lights up as soon as we turn the switch on...
  42. P

    What limits the speed of a computer or cell phone?

    I am just beginning to educate myself about electricity and computers. Every time I read something I realize my ignorance is even greater than I imagined. For instance, I was stunned to learn that the drift speed of a typical current is so slow. An AC circuit generates an electromagnetic field...
  43. G

    Why is the Drift Current of a PN Junction Independent of Bias?

    The magnitude of a drift current density is given by J = qnv, where q is the carrier charge, n is the carrier density per unit volume, and v is the carrier drift velocity. q is a physical constant and n is independent of bias. But when an external electric field is applied, the minority charge...
  44. LotusTK

    Factors affecting drift velocity?

    Homework Statement I am having a look at drift velocity and i know essentially what it is, and i am now noting down the factors that effect the drift velocity of the charge carriers as i think its a useful thing to know. So, so far i have that the number of charge carriers will effect the...
  45. U

    What Factors Affect Drift Velocity in Semiconductors?

    Homework Statement [/B] (a) Explain the terms intrinsic, extrinsic, mobility and effective mass in semiconductors (b) What is a hole and explain its mass and charge (c) Why is mobility of holes often less than mobility of electrons? Find the number density of holes and electrons (d) Find the...
  46. kelvin490

    Average drift velocity of electron in conduct

    I have a question on the derivation of the average drift velocity in a conductor: drift velocity is the average velocity which a free charge moving in a conductor has due to the influence of an electric field applied to the conductor. In a metal, the free charge will be an electron. As they move...
  47. gracy

    How Is Drift Calculated in River Boat Problems?

    What is drift in river boat problems?Is it velocity of river divided by time taken o reach the point aimed?Or velocity of river-countering velocity of swimmer or boat in the direction of boat velocity divided by time taken o reach the point aimed?In the below video , although the accent is...
  48. B

    Bi) Correct. Your solution is also correct.

    Homework Statement [/B] Can someone confirm if I answered correctly? Thanks Ai) Define the term drift velocity with reference to a current in a circuit. ii) Derive an expression to describe the current passing through a metallic conductor of cross-sectional area A having n charge carriers per...
  49. H

    Drift velocity: Why not 1/2 *t*(eE/m)

    Why is the drift velocity of an electron in a wire defined as: tau*(E*e/m) and not 1/2 *tau* (eE/m) as it is the AVERAGE VELOCITY!? because the above defintion of drift velocity is the velocity that is attained before the collision so rather the maximum velocity of the elctron, isn't it?
  50. I

    Electron Drift Velocity in Semiconductors

    Homework Statement "The low [electron] density of a semiconductor means that the conduction electrons travel much faster than they do in conductors." In order to fully understand this, I feel that I need to know why this occurs. Homework Equations I = nAve Where: I = current n = electron...
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