Energy in an Inductor: an Insulated Wire of Diameter 1

Multiple Choice

Energy in an inductor: An insulated wire of diameter 1.0 mm and negligible resistance is wrapped tightly around a cylindrical core of radius 5.0 cm and length 30 cm to build a solenoid. What is the energy stored in this solenoid when a current I = 0.20 A flows through it? (μ₀ = 4π × 10^-7 T ∙ m/A)

A) 1.2 × 10^-4 J
B) 9.6 × 10^-4 J
C) 4.8 × 10^-4 J
D) 2.4 × 10^-4 J
E) 5.9 × 10^-5 J