Problem 3.247

A non-conducting sphere of radius \(R=50 \mathrm{~mm}\) charged uniformly with surface density \(\sigma=10.0 \mu \mathrm{C} / \mathrm{m}^{2}\) rotates with an angular velocity \(\omega=70\) rad/s about the axis passing through its centre. Find the magnetic induction at the centre of the sphere.