Q7. The figure shows the cross-section of a hollow cylinder of inner radius a = 5.0 cm and outer radius b = 7.0 cm. A uniform current density of 1.0 A/cm2 flows through the cylinder parallel to its axis. Calculate the magnitude of the magnetic field at a distance of d= 10 cm from the axis of the cylinder. (μ0-4x × 10-7 T. m/A) = Ab d