Question

The magnetic field at a distance of 20.0 cm from a wire is 10.0 x 10^-7 T. The wire, which is straight, has a current that passes through it. Determine the current.

Answer 1

$\text{Solution :}\\ \text{Magnetic field due to long wire is given by : }\\ B = \dfrac{\mu_o}{4\pi} \dfrac{2I}{r}\\ \text{We have : } \\ \dfrac{\mu_o}{4\pi} = 10^{-7}T.m/A \\ B = 10.0\times 10^{-7}T\\ \text{ Distance } r = 20.0cm= 0.20\ m \\ \text{ Plugging in these in the above equation, we get; }\\ 10.0\times 10^{-7}T = (10^{-7}T.m/A) \times \dfrac{2\times I}{0.20\ m}\\ or\\ \text{ Current } \ I = 1\ A$