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?
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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...
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...
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...
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
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...
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
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
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
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...
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...
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))...
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...
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...
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...
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...
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.
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...
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...
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...
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...
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...
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...
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...
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)
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?
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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?
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...