Q.18 Physics · Section A ⭐ 360° Option Elimination Active

NEET 2024 Physics Question 18 Solution

Topic: Magnetism and Matter · Official NTA Booklet Code T1

Question

Match List I (Material) with List II (Susceptibility (χ)). List I: A. Diamagnetic; B. Ferromagnetic; C. Paramagnetic; D. Non-magnetic. List II: I. χ = 0; II. 0 > χ ≥ −1; III. χ >> 1; IV. 0 < χ < ε (a small positive number). Choose the correct answer from the options given below:

✓

Verified Against NTA Final Answer Key

Option (3) : A-II, B-III, C-IV, D-I

📚 Magnetism and Matter Easy

📋 Given Parameters & Problem Setup

Material A Diamagnetic

Material B Ferromagnetic

Material C Paramagnetic

Material D Non-magnetic

⚡

The 30-Second Exam Hall Shortcut: ⚡ Susceptibility Characteristic Sign Hack

⏱️ Save ~45 seconds

Diamagnetic is negative (0 > χ ≥ -1 -> A-II); Ferromagnetic is huge (χ >> 1 -> B-III); Non-magnetic has χ = 0 -> D-I!

1 Diamagnetic substances have negative susceptibility: -1 ≤ χ < 0 (matches II -> A-II).

2 Ferromagnetic substances have very large positive susceptibility: χ >> 1 (matches III -> B-III).

3 Paramagnetic substances have small positive susceptibility: 0 < χ < ε (matches IV -> C-IV).

4 Non-magnetic substances (vacuum) have zero susceptibility: χ = 0 (matches I -> D-I).

5 Complete matching: A-II, B-III, C-IV, D-I -> Option (3) in under 10 seconds!

🛡️

Why You Can 100% Trust This Shortcut: NCERT Physics · Magnetism and Matter (Magnetic susceptibility classification of dia-, para-, and ferromagnetic materials).

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Definition of Magnetic Susceptibility

Magnetic susceptibility χ is a dimensionless proportionality constant that indicates the degree of magnetization M of a material in response to an applied magnetic field H:

\chi = \frac{M}{H}

Step 2

Diamagnetic Materials (A)

Diamagnetic materials develop magnetization opposite to the applied field. Their susceptibility is negative and small, with superconductor limit χ = -1 (ideal diamagnetism):

-1 \le \chi < 0 \quad (0 > \chi \ge -1) \implies \text{A-II}

Step 3

Ferromagnetic Materials (B)

Ferromagnetic materials possess spontaneous domain alignment and magnetize strongly in the direction of the applied field. Their susceptibility is positive and very large (typically 1000 to 100,000):

\chi \gg 1 \implies \text{B-III}

Step 4

Paramagnetic Materials (C)

Paramagnetic materials possess permanent atomic dipole moments that weakly align with the applied field. Their susceptibility is positive, small, and temperature-dependent:

0 < \chi < \varepsilon \quad (\text{small positive number}) \implies \text{C-IV}

Step 5

Non-Magnetic Materials (D)

A completely non-magnetic substance (or vacuum) cannot be magnetized by an applied magnetic field, so its magnetization M = 0 and susceptibility is identically zero:

\chi = 0 \implies \text{D-I}

⭐

360° Option Elimination Engine Key Feature

Diagnose every choice: Know exactly why the right option works and why distractors fail.

4-Option Deep Scan

1 (1)

✗ Incorrect

Verdict & Scientific Reason:

Assigns large positive susceptibility to diamagnetic materials.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing ferromagnetic with diamagnetic.

2 (2)

✗ Incorrect

Verdict & Scientific Reason:

Assigns negative susceptibility to paramagnetic materials.

⚠️

Student Fallacy (Why candidates pick this trap): Swapping signs of diamagnetic and paramagnetic materials.

3 (3)

✓ 100% Correct

Verdict & Scientific Reason:

Flawless canonical alignment of magnetic susceptibilities.

💡

Why this is airtight: None.

4 (4)

✗ Incorrect

Verdict & Scientific Reason:

Assigns χ = 0 to ferromagnetic materials.

⚠️

Student Fallacy (Why candidates pick this trap): Gross confusion of magnetic classes.

⚠️

NTA Trap Alert: Swapping Diamagnetic and Paramagnetic Signs

Students frequently forget which one is negative. Diamagnetism is the ONLY class with negative susceptibility.

🛡️ How to avoid the -1 mark: Remember: DIA = Disagree = Negative (χ < 0). PARA = Positive (χ > 0).

📖

Core NEET Syllabus Standard

Physics Core Magnetism · Magnetism and Matter Standard Benchmark

Core Scientific Principle Tested:

"Diamagnetic: -1 ≤ χ < 0; Paramagnetic: 0 < χ < ε; Ferromagnetic: χ >> 1; Non-magnetic: χ = 0."

Syllabus Focus: Magnetic Properties of Materials

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

Dia is Down (Negative), Ferro is Far-up (Huge), Non is Null (Zero)!

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NEET 2024 Physics Question 18 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Susceptibility Characteristic Sign Hack

Step-by-Step Rigorous Workflow & Mathematical Proof

Definition of Magnetic Susceptibility

Diamagnetic Materials (A)

Ferromagnetic Materials (B)

Paramagnetic Materials (C)

Non-Magnetic Materials (D)

360° Option Elimination Engine Key Feature

NTA Trap Alert: Swapping Diamagnetic and Paramagnetic Signs

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

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