AAI ATC Junior Executive 25 Mar 2021 Shift 3 Paper

A toroid has a core (non-ferromagnetic) of an inner radius of 23 cm and an outer radius of 28 cm, around which 4000 turns of a wire are wound. If the current in the wire is 9 A, find the magnetic field (a) inside the core of the toroid and (b) outside the toroid?