The volume current for a solid sphere of radius R and total charge Q uniformly distributed through- out its volume that is rotating with angular velocity w = wî is 3Qwr sin 0 4т R3 J(r) = where (r, 0, ø) are the usual spherical coordinates. Using the Biot-Savart law, compute the magnetic field B(z) along the z-axis (both inside and outside the sphere).

The volume current for a solid sphere of radius R and total charge Q uniformly distributed through- out its volume that is rotating with angular velocity w = wî is 3Qwr sin 0 4т R3 J(r) = where (r, 0, ø) are the usual spherical coordinates. Using the Biot-Savart law, compute the magnetic field B(z) along the z-axis (both inside and outside the sphere).