Problem

A cylindrical long wire of radius

R

carries a current

I

uniformly distributed over the cross-sectional area of the wire. The magnetic field at a distance

x

from the surface inside the wire is (a)

\frac{\mu_0 I}{2\pi(R-x)}

(b)

\frac{\mu_0 I}{2\pi x}

(c)

\frac{\mu_0 I}{2\pi(R+x)}

(d) None of these