A non-conducting sphere of radius R=50 mmR=50 \mathrm{~mm}R=50 mm charged uniformly with surface density σ=10.0μC/m2\sigma=10.0 \mu \mathrm{C} / \mathrm{m}^{2}σ=10.0μC/m2 rotates with an angular velocity ω=70\omega=70ω=70 rad/s about the axis passing through its centre. Find the magnetic induction at the centre of the sphere.