What current is necessary to generate a field of 0.20 T inside a solenoid with 300 turns per cm?
A) 530 A
B) 5.3 A
C) 33 A
D) 0.33 A
E) 3.1 A

Question

Quizplus · Accepted Answer

The magnetic field inside a solenoid is given by $B = \mu_0 n I$, where $B$ is the magnetic field in teslas, $\mu_0$ is the permeability of free space ($4\pi \times 10^{-7}$ Tm/A), $n$ is the number of turns per meter, and $I$ is the current in amperes. Given $B = 0.20$ T and $n = 300$ turns/cm, which is $30000$ turns/m (since $1$ cm = $0.01$ m), we can solve for $I$. Rearranging the formula gives $I = B / (\mu_0 n)$. Substituting the given values, $I = 0.20 / (4\pi \times 10^{-7} \times 30000)$, which calculates to approximately $5.3$ A.

What Current Is Necessary to Generate a Field of 0