Average Electron Drift Distance with AC Current

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SUMMARY

The discussion focuses on calculating the average electron drift distance in a metal wire carrying a 60 Hz alternating current with a maximum current density of 100 amps/cm². The average drift velocity is derived using the equation vd = (-σEsin(ωt)) / (eNe), where J = -eNevd and J = σE. To find the average drift distance in one direction during a half-cycle of current, participants need to calculate the average absolute current density and the amount of coulombs moved per second, but lack values for σ and E.

PREREQUISITES
  • Understanding of AC circuit theory
  • Familiarity with electron mobility and drift velocity concepts
  • Knowledge of current density calculations
  • Basic grasp of electromagnetic equations
NEXT STEPS
  • Calculate the average absolute current density using the given maximum current density.
  • Determine the charge of an electron (e) and its role in drift velocity calculations.
  • Research the relationship between electric field (E) and conductivity (σ) in conductive materials.
  • Explore the effects of frequency on electron drift in AC circuits.
USEFUL FOR

Students in physics or electrical engineering, educators teaching AC circuit concepts, and professionals analyzing electron behavior in conductive materials.

achap6
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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 average drift distance of free electrons in one direction in a half-cycle of current?

Homework Equations


J = σE = σEsin(ωt)
ω = 2πν
J = -eNevd

The Attempt at a Solution


Part a:

J = -eNevd
-eNevd = σEsin(ωt)
vd = (-σEsin(ωt)) / (eNe)

Part b:

Need help here, I attempted to plug in ω = 2πν into the equation J = σEsin(ωt), but don't seem to be getting anywhere, because I don't have σ or E.
 
Last edited:
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achap6 said:
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.

Calculate the average absolute current density ( [ A/cm2 ] ).

Calculate the amount of coulombs moved per second.

Calculate the amount of centimeter wire-electrons is moved per second.
 

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