Physics

Problem

Which one of the following gives the magnitude of the magnetic field at a point located at a distance

r

from a very long straight conductor carrying a steady current

I

in free space? a)

B=\dfrac{\mu_{0} I}{\pi r}

B=\dfrac{\mu_{0} I}{4\pi r}

B=\dfrac{\mu_{0} I}{2\pi r}

B=\dfrac{\mu_{0} I}{2 r}