Line charge creating induced emf and displacement current

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SUMMARY

The discussion focuses on calculating the displacement current and magnetic flux through a square wire loop adjacent to a long, straight wire with a time-varying line charge, λ = λ0 exp(-βt). The relevant equations include idisp = ε0 * dΦe/dt and ε = -dΦm/dt, with Φm and Φe representing magnetic and electric flux, respectively. Participants express uncertainty about integrating the electric field derived from the time-varying charge and applying Faraday's Law to find the induced emf. Clarifications are sought regarding the geometry of the wire and loop in relation to their respective orientations.

PREREQUISITES
  • Understanding of electromagnetic theory, specifically displacement current and Faraday's Law.
  • Familiarity with calculus, particularly integration techniques for time-varying functions.
  • Knowledge of electric and magnetic flux concepts, including their mathematical representations.
  • Basic understanding of vector calculus to analyze the geometry of the wire and loop.
NEXT STEPS
  • Study the derivation of electric fields from time-varying charge distributions.
  • Learn about the application of Faraday's Law in calculating induced emf in circuits.
  • Research the relationship between electric and magnetic flux in dynamic systems.
  • Explore vector calculus techniques for analyzing geometric relationships in electromagnetic problems.
USEFUL FOR

This discussion is beneficial for physics students, electrical engineers, and educators focusing on electromagnetic theory, particularly those dealing with displacement current and induced emf in dynamic systems.

gsmtiger18
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Homework Statement


A long, straight wire has a line charge, λ, that varies in time according to: λ = λ0 exp(-βt). A square wire loop of dimension a is located adjacent to the wire at a distance of a from the wire. Calculate expressions for the displacement current at the center of the wire loop and the magnetic flux through the loop.

a = the side length of the square wire loop.
λ0 = the initial charge of the line charge at time t = 0
β = I assume some kind of constant. I haven't encountered this variable in a displacement current problem before.

Homework Equations


idisp = ε0 * dΦe/dt
ε = -dΦm/dt
Φm = ∫B ⋅ dA
Φe = ∫E ⋅ dA = qenc / ∈0
∫ E ⋅ dl = -dΦm / dt

The Attempt at a Solution


I'm pretty sure I can find an expression for the electric field first by integrating the equation for the time-varying charge, but I'm not sure how to set that up. I think I should integrate with respect to time and treat radius as a constant. From the electric field I can use Faraday's Law to find the emf, but again I'm unsure as to how exactly to set up the math.
 
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What is the juxtaposition between the wire direction vector and the normal to the loop? I.e if the wire vector is in the x direction, is the loop normal in the y or the z direction?

Is "a" the distance from the loop's center to the perpendicular distance to the wire, or is "a" the perpendicular distance from the closer collinear loop segment to the wire?

A picture would help immensely.
 
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