📘 Theory Notes
Magnetic Dipole Moment: M = m × (2l)
Magnetic Field on Axis: B = (μ₀ / 4π) × (2M / r³)
Magnetic Field on Equatorial Line: B = (μ₀ / 4π) × (M / r³)
Bar Magnet Properties: North → South outside, South → North inside
âš¡ Important Formulas
- Torque: τ = M × B
- Potential Energy: U = -M·B
- Magnetization: M = magnetic moment / volume
- Relation: B = μ₀ (H + M)
🔥 PYQs (Previous Year Questions)
Q1: Magnetic field at center of bar magnet depends on?
Q2: Torque on magnetic dipole in uniform field is zero when?
🧠MCQs Practice
Q1: SI unit of magnetic moment?
A) Tesla B) Ampere-m² ✅ C) Weber D) Newton
Q2: Direction of magnetic field lines inside magnet?
A) N→S B) S→N ✅ C) Circular D) Random
🚀 Tricks & Shortcuts
- Axis field = 2 × Equatorial field
- Torque max when θ = 90°
- Inside magnet: S → N (reverse)