Chapter 7, Problem 15STP

To determine

To state: Similarities and differences between a permanent magnet and an un-magnetized iron.

Explanation of Solution

Introduction:

When a magnet is brought close to a piece of iron, it gets magnetized and exhibits the properties of a magnet.

Similarities between a permanent magnet and an un-magnetized iron are as follows:

1. Atoms of both have magnetic domains
2. Both get attracted to magnets.

Differences between a permanent magnet and an un-magnetized iron are as follows:

1. An un-magnetized iron becomes a magnet when another magnet is brought close to it or when an electric current is passed. A permanents magnetic exhibits properties of a magnet even without these conditions.
2. Magnetic domains of a magnet are always aligned while that of an un-magnetized iron are unaligned.

Conclusion:

A permanent magnet and an un-magnetized iron are not entirely similar or different.