Chapter 7.1, Problem 5R

To determine

To explain: Changes in magnetic field of a bar magnet on heating.

Explanation of Solution

Introduction:

In a magnetic material, the magnetic poles of a group of atoms, point in the same direction. These groups of atoms are called magnetic domains.

On heating a bar magnet, the atoms of the magnet move rapidly on acquiring kinetic energy. In doing so, they collide with one another. This leads to a disarrangement of atoms in the domain. In other words, the magnetic poles of a group of atoms which earlier pointed in the same direction, do no more.

Conclusion:

Heating a bar magnet would reduce its magnetic field.