Sources of Magnetic Fields Explained | Chapter 28 of University Physics
Sources of Magnetic Fields Explained | Chapter 28 of University Physics Chapter 28 explores how moving charges and currents create magnetic fields, and how materials respond to those fields. You’ll master the Biot–Savart Law for calculating field contributions, Ampère’s Law for symmetric configurations, and the role of magnetic susceptibility and permeability in different materials. Watch the full video summary for detailed derivations and visualizations. Magnetic Field from a Moving Charge A single charge moving with velocity v generates a magnetic field given by the equation: B = (μ₀/4π) · [q v × r̂ / r²] Here, μ₀ is the magnetic constant, q the charge, and r̂ the unit vector from the charge to the field point. The field lines form closed loops and obey the superposition principle. Biot–Savart Law & Applications The Biot–Savart Law extends this idea to current elements: dB = (μ₀/4π) · [I dl × r̂ / r²] By integrating over a wire, you find: Long straight wir...