Which expression gives the magnitude of the magnetic field produced at a distance…

PHYSICS · Single correct · CBSE · Physics · Moving Charges and Magnetism · Moving Charges and Magnetism

Problem

Which expression gives the magnitude

B

of the magnetic field produced at a distance

r

from a long, straight wire carrying a steady current

I

in vacuum? (a)

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

(b)

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

(c)

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

(d)

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