The basic magnification curve for a ferromagnetic material is shown is figure. Then the value of relative permeability is highest for the point

for P            μ=BH=0.25103=0.25×10−3H/m for Q            μ=BH=0.752×103=0.375×10−3H/m for R             μ=BH=1.253×103=0.41×10−3H/m for S          μ=BH=1.56×103=0.25×10−3H/m