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Energy density in magnetic field B is:
Au = B²/(2μ) (J/m³) — for linear magnetic material
BB²/2
CB/μ
DμB
Answer & Solution
Correct answer: A. u = B²/(2μ) (J/m³) — for linear magnetic material
Magnetic energy density: u_m = B²/(2μ) = ½ BH (for linear). Electric field equivalent: u_e = ½ εE². Used in calculating energy stored in inductor: U = ∫u dV. EM waves: u_e = u_m (equipartition).
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