An Ideal Solenoid Is Wound with 470 Turns on a Wooden

Multiple Choice

An ideal solenoid is wound with 470 turns on a wooden form that is $4.0 \mathrm {~cm}$ in diameter and $50 \mathrm {~cm}$ Iong. The windings carry a current in the sense shown in the figure. The current produces a magnetic field of magnitude $4.1 \mathrm { mT }$ , at the center of the solenoid. What is the current $I$ in the solenoid windings? $\left( \mu _ { 0 } = 4 \pi \times 10 ^ { - 7 } \mathrm {~T} \cdot \mathrm { m } / \mathrm { A } \right)$

A) $4.3 \mathrm {~A}$
B) $3.0 \mathrm {~A}$
C) $3.9 \mathrm {~A}$
D) $3.5 \mathrm {~A}$
E) $2.6 \mathrm {~A}$