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//=====================================================================================
//Chapter 13 example 8
clc;clear all;
//variable declaration
d = 0.1; //diameter in m
a = 33.5*10^-6; //cross sectional area of iron ring in m^2
Ns = 220; //number of turns on secondary coil
Nm = 320; //number of turns on magnetising winding
I = 10; //current in A
B = 2.5*10^-3; //flux in Wb
n = 102; //reading of scale
g = 272; //galvanometer throw
//calculations
l = (%pi)*d; //mean length of iron ring in m
H = (Nm*I)/(l); //magnetising force with 10 A current
K = B/(n);
//2*phi*Ns = K*g
phi = (K*g)/(2*Ns); //flux in Wb
B1 = phi/(a); //flux density in Wb/m**2
u0 = 4*%pi*10^-7;
//B = u0*ur*H
x = u0*H;
//B = x*ur
//ur = B/x
ur = B1/x; //relative permeability
//result
mprintf("relative permeability = %3.1f",ur);
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