Current flows up the inner cylinder of a coaxial cable and returns on the outside cylinder. The radius of the inner cylinder is 0.1 cm, and the radius of the thin outer cylindrical shell is 0.5 cm. Calculate the magnetic field on the cylindrical surface midway between the inner and outer surfaces, given that the current is 10 A. Ignore end effects. (0=4×10−7 T∙m/A)