Practice question

**Bar magnet properties** include dipole moment m = pole strength × separation, unit A·m², field lines emerge from north and enter south outside. Lines never cross, ensuring single valued B at any point, and pattern reflects dipole nature with symmetric loops around magnet. B = (μ₀/4π) (2m/r³) . Given: m = 1.8 A m² , r = 0.6 m , (μ₀/4π) = 10⁻⁷ . B = 10⁻⁷ × (2 × 1.8/(0.6)³) = 10⁻⁷ × (3.6/0.216) = 1.67 × 10⁻⁶ T ≈ 1.7 × 10⁻⁶ T . Substituting values gives 1.7 × 10⁻⁶ T, which matches expected magnitude for this magnetic configuration, confirming dipole field dependence