Anna University Solved Problems in Magnetic Properties of Materials

ANNA UNIVERSITY SOLVED PROBLEMS

Problem 2.12

The magnetic field strength of copper is 10⁶ ampere/metre. If the magnetic susceptibility of copper is -0.8 x 10^-5, calculate the magnetic flux density and magnentisation in copper. (A.U. May 2014)

Given data

Magnetic field strength H = 10⁶ Am^-1

Magnetic susceptibility of copper χ = -0.8 x 10^-5

Solution

Problem 2.13

A magnetic field of 1800 ampere/metre produces a magnetic flux of 3 x 10^-5 weber in an iron bar of cross sectional area 0.2 cm². Calculate magnetic permeability. (A.U. May 2015)

Given data

Magnetizing field H = 1800 Am^-1

Magnetic flux = 3 x 10^-5 weber

Area of cross section A = 0.2 cm² = 0.2 x 10^-4 m²

Solution

Magnetic flux density B = φ / A

Substituting the given values, we have

Problem 2.14

The saturation magnetic induction of nickel is 0.65 weber / metre². If the density of nickel is 8906 kg/m³ and atomic weight is 58.7, calculate the magnetic moment of the nickel atom in Bohr magneton. (A.U. Dec 2016)

Given data

Solution

N is the number of atoms per unit volume (atoms/m³)

Substituting the given values, we have

Problem 2.15

A paramagnetic material has bcc structure with a cube edge of 2.5 Å. If the saturation value of magnetisation 1.8 x 10⁶ ampere / metre. Calculate the average magnetisation contributed per atom in Bohr magneton. (A.U. Dec. 2016)

Given data

Solution

Number if atoms per unit volume

Total magnetisation M = 1.8 x 10⁶ Am^-1

Average magnetisation produced per atom