---
title: "What is magnetization"
subject: "Electromagnetism"
chapter: 3
key: "semester_3/electromagnetism:magnetization-define"
source: https://www.bctengineer.com/q/semester_3/electromagnetism/magnetization-define
site: BCT Engineering
---

# What is magnetization

Electromagnetism · Chapter 3: Magnetic field

- Asked in: 2067 Shrawan, 1 marks
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/electromagnetism/magnetization-define
- Whole chapter: https://www.bctengineer.com/md/semester_3/electromagnetism/chapter-3

## Question

What do you understand by the term magnetization?

## Short answer

Magnetization M is the magnetic dipole moment per unit volume (A/m). It quantifies the net alignment of atomic magnetic dipoles and is related to the fields by B = μ₀(H + M), with M = χ_m H for linear materials.

## Answer

Magnetization **M** is the magnetic dipole moment per unit volume of a material: M = lim (Σ m)/Δv as Δv → 0, in A/m. It measures how strongly the atomic magnetic dipoles in a material are aligned by an applied field. It is related to the field by B = μ₀(H + M), and for a linear material M = χ_m H, where χ_m is the magnetic susceptibility.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Magnetization M is defined as:
   A. Magnetic flux per unit area
   B. Magnetic dipole moment per unit volume
   C. Force per unit pole
   D. Current per unit length
   Answer: B. M = lim (sum of dipole moments)/dv as dv tends to 0, in A/m. (Key point: Definition)

2. Which relation connects B, H and M?
   A. B = mu0 (H + M)
   B. B = mu0 (H - M)
   C. B = H + M
   D. B = mu0 H M
   Answer: A. B = mu0 (H + M) in a magnetised material. (Key point: Relation to B and H)

3. In a linear material M equals:
   A. mu_r H
   B. chi_m H
   C. H / chi_m
   D. mu0 H
   Answer: B. M = chi_m H, where chi_m is the magnetic susceptibility. (Key point: Linear materials)

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