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 ?

Explanation

`R=15 cm, N = 3500,mu_r=800 " "B = ? , I = 1.2 A`
`B=(mu_0mu_rNI)/(2piR)=(4pixx10^(-60)xx800xx3500xx1.2)/(2pixx15xx10^(-12))=4.48T`