which wire, when current flows through it, would be surrounded by the strongest magnetic field?
which wire, when current flows through it, would be surrounded by the strongest magnetic field?
Answer
Explanation:
Step1: Recall magnetic - field formula
The magnetic field due to a current - carrying wire is related to the current and the geometry of the wire. For a long straight wire, the magnetic field at a distance $r$ from the wire is given by $B=\frac{\mu_0I}{2\pi r}$. For a circular loop of wire, the magnetic field at the center of the loop is $B = \frac{\mu_0NI}{2R}$, where $N$ is the number of turns, $I$ is the current, and $R$ is the radius of the loop.
Step2: Compare the two cases
Assume the same current $I$ flows through both wires. The circular loop (the coiled wire) has multiple turns ($N > 1$ if it is coiled), while the straight wire has $N = 1$. The magnetic field of a circular loop is enhanced by the number of turns.
Answer:
The coiled wire (the second wire in the picture)