Magnetic shielding is done using materials with large permea

Magnetic shielding is done using materials with large permeability, like \"Mumetal\" (u/u₀~10⁵). Calculate the field inside a spherical cavity of radius R that is surrounded by a concentric spherical shell of permeability u, if there is an external applied field B=B₀k^{^}

Solution

Magnetic field inside the shield is given by

B = B0/u_r = B0/(u/u0) = B0/10^5 k^ answer