Question

A Rowland ring of mean radius 15 cm has 3500 turns of wire wound on a ferromagnetic core of relative permeability 800. What is the magnetic field B in the core for a magnetising current of 1.2 A?

Answer 1

I = 1.2 A

μ_r = 800

a = 15 cm = 0.15 m

Total number of turns = 3.500

Length over which the wire is wound,

I = 2πa

= 2π x 0.15 m

Total number of turns per unit length,