# Question #d61af

Jan 20, 2018

It depends on the strength of the electric current, the distance from the current, and the geometry of the current being conducted.

#### Explanation:

When you say the power of magnetic, I assume you mean the strength of the magnetic field. "Power" in physics has a very specific meaning. f

Phenomenologically, we learn from experiments that electric current produces magnetic field. The nature just does it. We don't know exactly why it does it. Just like we don't why gravity attracts matter, it just does.

The strength magnetic field (B) produced by a straight wire conducting electric current (I), i.e., moving charges, is directly proportional to the strength of the electric current and inversely proportional to the distance directly from the straight wire,

${B}_{\text{induced }} \approx \frac{I}{r}$

Hence, the strength of the magnetic field of a point in space near the current depends on how strong the current is and how far is the point from the current. The closer it is to the current, the stronger is the magnetic field.

However, if the wire carrying the current is no longer in a straight line but it bent to form curves, loops or other geometric shapes, the strength of the magnetic field at same point will be different.

Also, magnetic field has direction. Its effective direction changes if the geometry of wire arrangement also changes.

So far this is just current derived from one current, you could have magnetic fields come collectively from multiple currents carried by different wires.