Q1. [2] § 12.1 MAGNETIC FIELD AND FIELD LINES § 12.2.4 Magnetic Field due to a Current in a Solenoid § 12.3 FORCE ON A CURRENT-CARRYING CONDUCTOR IN A MAGNETIC FIELD
Name the device used to magnetise a piece of magnetic material. Draw a labelled diagram to show the arrangement used for the magnetisation of a cylinder made of soft iron.
Previously asked in CBSE board exam
2024 31/3/1 Q25(b)
Generated by claude-sonnet-4-6 · 2026-06-15 06:51 · grounding rag
Model Answer
Device used: Solenoid (a coil of insulated copper wire carrying electric current).
Diagram:
```
Battery (B)
+---|===|---+
| |
| S N |
====|============|==== ← Solenoid coil
| [soft iron cylinder inside]
| |
+-----------+
Switch (K)
```
A soft iron cylinder is placed inside a current-carrying solenoid. The strong uniform magnetic field inside the solenoid magnetises the soft iron, forming an electromagnet.
Source: Chapter 12, Section 12.2.4
---
Explanation
- The key device is a solenoid connected to a battery.
- The diagram must show: the solenoid coil, soft iron core inside, battery, and switch — all labelled. Examiners award 1 mark for naming the device and 1 mark for the correct labelled diagram.
- Remember: the magnetic field inside a solenoid is uniform, which is why it effectively magnetises the material placed inside it.
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