A Long, Straight Wire with 3

Multiple Choice

A long, straight wire with 3.0 A current flowing through it produces magnetic field strength 1.0 T at its surface. If the wire has a radius R, where within the wire is the field strength equal to 36% of the field strength at the surface of the wire? Assume that the current density is uniform throughout the wire. (μ₀ = 4π × 10^-7 T ∙ m/A)

A) 0.36 R
B) 0.060 R
C) 0.64 R
D) 0.030 R