Drude model Definition and 16 Threads

  1. A

    I Drude model with and without an electric field

    Why in the Drude model without e-field no energy is transfer by electrons to ions, but when there is an e-field electrons transfer energy to ions ?
  2. Sunny Singh

    Relaxation time and average electron velocity in Drude model

    If τ is the relaxation time, τ means, on average the time between two collisions for an electron moving under a constant electric field inside a metal. Now according to the assumptions of drude model, the electron acquires an additional velocity of \frac{-eEt}{m}where t is the time elapsed since...
  3. S

    I Running through a complex math derivation of plasma frequency

    Background of problem comes from Drude model of a metal (not necessary to answer my problem but for the curious): Consider a uniform, time-dependent electric field acting on a metal. It can be shown that the conductivity is $$\sigma = \frac{\sigma_0}{1-i\omega t}$$ where $$\sigma_0 =...
  4. I

    I Drude Model Permittivity Formula - e^iwt or e^(-iwt)?

    I've been having a sign problem while deriving the permittivity formula using Drude model, and I found out that the problem came from the fact that complex field vectors are expressed with e-iwt, not eiwt, thus producing (-iwt) term when differentiated...
  5. spareine

    Why is the refractive index for red lower than for blue?

    By observing that red is the outermost color of the rainbow it is possible to conclude the refractive index of water, n, is lower for red than for blue. However, why is n lower for red? This seems to be answered by the Drude dispersion model, with a resonance in the ultraviolet region, but I...
  6. chandrahas

    B Does the Drude Model Account for J Cross B Force in Hall Conductivity?

    I was thinking about hall conductivity, when this question popped up. If there is a magnetic field and an electric field perpendicular to it, then a hall current is generated since the ions have larger gyro radii compared to electrons. Now this current would produce a J cross B force in the...
  7. Aaron young

    Reworking of the Drude model using scattering statistics

    Homework Statement The problem I have been set is to rework the Drude model using clearly defined scattering statistics. Homework Equations The Drude model as we have been given it is in terms of momentum \vec{p}(t+dt)=(1-\frac{dt}{\tau})(\vec{p}(t)-q\vec{E}(t)dt)+(\frac{dt}{\tau})(0) Where...
  8. C

    Drude model relaxation time approximation

    In the Drude model of the free electron gas to explain the conduction of a metal, the relaxation time approximation that the electron has a collision in an infinitesimal time interval ##dt##is ##dt/\tau##. It can be shown that the mean time between collisions is ##tau##. If we choose an...
  9. F

    Does the Drude model predict the emission of em waves?

    The Drude model of electrical conduction has the charge carriers being accelerated by an electric field and then interacting with the lattice ions. The cycle is then repeated. An unbound charged particle if accelerated emits electromagnetic waves. Does that mean that a prediction of the Drude...
  10. C

    Drude model electron interaction

    In every source I've checked so far, we make the assumption that we can neglect electron-electron interaction in this model but they always fail to give any reason to answer why this is plausible. Does anyone know how physicists convinced themselves of this at the time and even now (other than...
  11. A

    Drude Model: Electrons & Collisions

    As far as I understand: In the Drude model we take the electron to be moving in a random direction after each collision (*), such that the mean velocity is simply the average of -eEt/m, which is just -eEτ/m, where τ is the relaxation time. But I am very confused about this basic assumption...
  12. T

    What is Not Directly Proportional to Current Density in the Drude Model?

    Homework Statement In the drude model of electrical conduction, the current density (J) is not directly proportional to : a. The average time interval between sucessive collisions b. the number of charge carriers per unit volume c. The square of the electron charge d. The electric field...
  13. Z

    Solid State - Sommerfeld Drude Model, Calculating N of Elect.

    Hello PF :) Homework Statement Consider a system of N electrons at temperature T = 0, each having a mass of m, confined to volume V. Find the number of electrons that: a) have momentum p<p_f/2 b) ... Homework Equations The relevant equations can be derived below: but here is a...
  14. I

    Is Free-electron model := Drude Model (of metals) ?

    Is the free-electron model synonymous with Drude model? or is Drude model a special subset of the free-electron model? I have seen texts that refer to a "free-electron model" and do not mention Drude's name. and i have also seen texts use these two terms interchangeably. Sorry, i have no...
  15. I

    Ohm's Law derivation from Drude Model

    I'm having trouble understanding the derivation of Ohm's law from the drude model. So you start with a simple sum of forces: \Sigma F_x = - e \: E + F_{collision} = 0 (my understanding is that there are only two forces in Drude's model: those from electron-ion collisions and applied...
  16. T

    Can the Drude Model Explain Scattering Time in Terms of Unit Conversion?

    I got the answer of the hw, but still have question about it. I need to calculate the scattering time μ = eτ / m. τ is the mean time. the unit needs to be in cm^2 / V.S I put the unit like this : e = coulumb τ = s m = kg then it's impossible to get the unit like that. Then I'm...
Back
Top