Practice portal › Electromagnetic Induction › Self-Inductance
Asked in GSEB Board March 2020 · Energy stored in an inductor
Idea: take a long solenoid and share its stored energy over the volume its field fills.
Stored energy: U=1/2LI² with L=μ₀n²Aℓ.
Field inside: B=μ₀nI, so I=B/(μ₀n).
U=1/2μ₀n²Aℓ·(B²)/(μ₀²n²)=(B²)/(2μ₀) Aℓ.
The field fills the volume Aℓ, so the energy per unit volume is u=(B²)/(2μ₀).
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