Magnetic Field inside and outside wire

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SUMMARY

The discussion focuses on calculating the magnetic field both inside and outside a cylindrical wire carrying current I, with charge density j and radius R. The Biot-Savart Law and Ampère's Law are identified as the primary equations for this analysis. The magnetic field inside the wire is determined to be B = μ₀I / (2πr), while the magnetic field outside the wire is given by B = μ₀I / L, indicating that the magnetic field outside the wire is independent of the wire's radius.

PREREQUISITES
  • Understanding of Biot-Savart Law
  • Familiarity with Ampère's Law
  • Knowledge of magnetic field concepts
  • Basic principles of current density (j) and charge density
NEXT STEPS
  • Study the derivation of the Biot-Savart Law in detail
  • Explore applications of Ampère's Law in different geometries
  • Investigate the concept of magnetic fields in solenoids
  • Learn about the implications of current density in electromagnetic fields
USEFUL FOR

Physics students, electrical engineers, and anyone studying electromagnetism or magnetic field theory.

Chip90
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Homework Statement



There is a wire with current I ,charge density j, and radius R. Find the Magnetic Field outside the wire (a>r) and inside the wire (a<r).

Homework Equations



Biot- Savart or Amperes law

I=JdotA

The Attempt at a Solution



Not sure how to attempt it or which equation to use. From my previous question about solenoids, I know that Magnetic Field only depends on length of L, not radius of wire..
 
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Once you are inside the wire the total current depends on r in the way that you are still adding in more current to your amperian loop as you slowly go through the wire. Once you leave the wire, the amount of current enclosed in the amperian loop stays the same, and so the current does not depend on r in this case.
 
ok so to find the inner B field, I use
792d084dfe4651c02d935c1490df17cd.png


which would lead me to say

B=Uo*I/ 2*pi*r

and for the outer

B=Uo*I/L
 

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