A long straight wire of radius R = 1 cm carries a total current I = 1 Amp
which flows uniformly through the cross-section of the wire. Draw a diagram of this wire and the
current and the magnetic field which is produced. Using Ampere’s law solve for the magnitude of
the magnetic field as a function of the radial distance for both the cases r < R and r > R. With
pencil and paper, plot this magnitude as a function of the radial distance r (with the vertical
coordinate being |~B| and the horizontal coordinate being r).