A very long wire generates a magnetic field of 0.0050 × 10^-4 T at a distance of 3.0 mm. What is the magnitude of the current?

Question

Quizplus · Accepted Answer

The magnetic field of a long wire is given by:$$B = \frac{\mu_0 I}{2\pi r}$$where:* B is the magnetic field in teslas (T)* μ0 is the permeability of free space (4π × 10^-7 T·m/A)* I is the current in amperes (A)* r is the distance from the wire in meters (m)We can rearrange this equation to solve for the current:$$I = \frac{2\pi rB}{\mu_0}$$Plugging in the given values, we get:$$I = \frac{2\pi (0.003 \ m)(0.0050 	imes 10^{-4} \ T)}{4\pi 	imes 10^{-7} \ T\cdot m/A} = 7.5 \ mA$$Therefore, the magnitude of the current is 7.5 mA.

A Very Long Wire Generates a Magnetic Field of 0