A cylindrical bar magnet ( radius = 1 cm , length = 10 cm ) has field intensity of 1000 A/m . The magnetic moment  in the bar if permeability of its material is 6.3×10−4H/m  is ----------

We know  μ=μ0(1+χ)                                    χ=μμ0−1=6.3×10−44π×10−7−1 ≃ 500Intensity of magnetizationI=χH=500 × 1000=5×105A/m⇒Magnetic moment  (M)=I V                                                 ⇒M=Iπr2L⇒M=5×105×3.14×(10−2)2×(10×10−2)⇒M=15.70Am2