Various Terms Related to Magnetism – Complete Notes, Revision, Important Questions & Downloads
Various Terms Related to Magnetism gathers the working vocabulary that the rest of the chapter depends on, especially Intensity of Magnetisation and Susceptibility, and it also links those ideas to field, flux, permeability, and magnetising field. NEET tests this topic through quick-definition questions, unit comparisons, and relation-based formulas such as I = m/A = M/V and mu_r = 1 + chi_m. A typical scoring move is to identify whether a quantity is scalar or vector and then connect B, H, I, and susceptibility without mixing magnetisation with magnetising field.
NEET Weightage & Exam Pattern
Magnetism| NEET Year | Questions from this Topic | Bar | Marks |
|---|---|---|---|
| 2024 | 1 | 4 | |
| 2023 | 1 | 4 | |
| 2022 | 1 | 4 | |
| 2021 | 1 | 4 | |
| 2020 | 1 | 4 | |
| Topic Weightage | 5 | 20 |
The relation B = mu0(H + I) and therefore mu_r = 1 + chi_m is one of the cleanest bridge formulas between field terms and material response.
Most mistakes come from treating H, I, and B as interchangeable because all appear in the same chapter but describe different physical roles.
Preparation Strategy
Sort Every Symbol by Job Treat H as the magnetising field applied from outside, I as the magnetisation developed in the material, and B as the resulting flux density. This immediately removes most symbol confusion.
Memorise the Dimensionless Quantity Magnetic susceptibility chi_m is the ratio I/H and has no units. NEET often asks this because it is the cleanest way to distinguish it from B, H, and I.
Use the Bridge Formula Actively From B = mu0(H + I), substitute I = chi_m H to get B = mu0H(1 + chi_m). This derivation is short enough to reconstruct during the exam if the final relation slips.
Keep SI and CGS Unit Questions Separate Flux, flux density, magnetising field, and susceptibility each have different unit behaviour. Do not rely on memory blur; revise one unit table once and then test yourself on it.
Download Topic Notes
PDF · Cheat Sheet · MCQ Set · PYQTopic Coverage
2-Column Table| Column A | Column B |
|---|---|
Quick Revision
Concept → Trap → Example1) Intensity of Magnetisation and Susceptibility
Material ResponseIntensity of magnetisation I tells how strongly the material itself becomes magnetised, while susceptibility chi_m = I/H tells how easily that magnetisation is produced by an applied field. With B = mu0(H + I), the relative permeability follows as mu_r = 1 + chi_m.
- I can be written as pole strength per unit area or magnetic moment per unit volume, so it is a vector quantity with SI unit ampere per metre.
- chi_m is scalar and dimensionless because it is a ratio of two like field-strength quantities.
- Trap: H is not the same as B; H describes magnetising effort, while B describes resulting flux density in the medium.
US Curriculum Gaps
Note for NRI/OCI students studying abroad.Notation Density Is Usually Lighter Elsewhere
Many curricula spread magnetisation, susceptibility, and permeability across separate units, while NEET can ask them together in one direct MCQ.
- distinguish H from B quickly
- remember chi_m is unitless
Unit Conversion Is a Real Exam Lever
Tesla, weber, gauss, oersted, and ampere per metre all appear around the same topic, so precise unit ownership matters more than casual familiarity.
- 1 tesla = 10^4 gauss
- 1 oersted = 80 A/m in the text convention
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Physics Revision Checklist
Use this section for quick chapter tracking before mocks, part tests, and final NEET revision.
Frequently Asked Questions
Notes · Downloads · Revision · Important QuestionsWhat is the difference between magnetic flux and magnetic flux density?
Why is magnetic susceptibility dimensionless?
What does intensity of magnetisation physically mean?
How is relative permeability connected to susceptibility?
Is B the same as H?
Why does NEET ask units so often in this topic?
What is the common trap in the B = mu0(H + I) relation?
Where does permeability enter physically?
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