A long, hollow, cylindrical conductor (with inner radius 2.0 $\mathrm{mm}$ and outer radius 4.0 $\mathrm{mm}$ ) carries a current of 24 $\mathrm{A}$ distributed uniformly across its cross section. A long thin wire that is coaxial with the cylinder carries a current of 24 $\mathrm{A}$ in the opposite direction. What is the magnitude of the magnetic field (a) 1.0 $\mathrm{mm}$ ,
(b) $3.0 \mathrm{mm},$ and $(\mathrm{c}) 5.0 \mathrm{mm}$ from the central axis of the wire and
cylinder?