Solenoid Field Strength - Missing Raduis?

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SUMMARY

The discussion focuses on calculating the magnetic field strength inside a long solenoid with 35 turns per centimeter and a current of 4.0A. The correct formula to use is B = μ₀ * I * n, where μ₀ is the permeability of free space, I is the current, and n is the number of turns per unit length. The confusion arises from the incorrect application of the formula for a circular coil, which is not suitable for long solenoids. Participants emphasize the importance of using the appropriate equations derived from Ampere's law for accurate calculations.

PREREQUISITES
  • Understanding of Ampere's law
  • Familiarity with magnetic field concepts
  • Knowledge of solenoid characteristics
  • Basic algebra for manipulating equations
NEXT STEPS
  • Study the derivation of the magnetic field inside a solenoid using Ampere's law
  • Learn about the permeability of free space (μ₀) and its significance in electromagnetism
  • Explore the differences between short and long solenoid formulas
  • Practice solving problems involving solenoid field strength with varying parameters
USEFUL FOR

Students studying electromagnetism, physics educators, and anyone interested in understanding solenoid behavior and magnetic field calculations.

Euler2718
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Homework Statement



A long solenoid has 35 turns/cm. With a current of 4.0A, what is the field strength at the core?

Homework Equations



[tex]\beta = \frac{\mu N I}{2r}[/tex]

The Attempt at a Solution



I have no idea with the radius is; that's the entire problem statement above.
 
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The formula you gave is for a circular coil of short length. A different formula applies to the long solenoid. Check your notes or textbook.
 
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Using Ampere's law, we can derive the magnetic field inside a solenoid. It is B = u_o i n, where n is turns/length
 
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