Electricity & Magnetism
Energy Density (Electric Field)
Energy stored per unit volume in an electric field.
Variables
uJ/m³
Energy density
Energy per unit volume
ε₀F/m
Permittivity
8.85×10⁻¹²
EN/C
Electric field
Field strength
Derivation
From U = ½CV² and C = ε₀A/d, u = U/Volume = ½ε₀E².
Your notes
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Common questions
What is the Energy Density (Electric Field) formula?
Energy Density (Electric Field) is written u = 1/2ε₀ E². Energy stored per unit volume in an electric field. It belongs to Electricity & Magnetism, under Capacitance.
What are the units in u = 1/2ε₀ E²?
In SI units, u is energy density, measured in kg/(m·s²); ε₀ is permittivity, measured in A²·s⁴/(kg·m³); E is electric field, measured in kg·m/(A·s³).
How is the Energy Density (Electric Field) formula derived?
From U = ½CV² and C = ε₀A/d, u = U/Volume = ½ε₀E². The result is u = 1/2ε₀ E².