Question

A permanent magnet can lose its magnetism with time.
A. True
B. False

Answer 1

Hint: Recall that permanent magnets are ferromagnets. In other words, the behaviour of permanent magnets is consistent with the domain theory of magnetism. Now, think of what would happen to the atoms in the so-called domains if they were always subjected to temperature fluctuations or were always being dropped and poorly handled. This should give you enough reasons to arrive at a justification for the choice you make.

Complete answer:
Let us begin by understanding what a permanent magnet is.
Permanent magnets are materials that generate a persistent magnetic field owing to the internal structure of the materials themselves. These materials retain their ferromagnetic property for a long period of time, which is why they are called permanent magnets. A naturally occurring permanent magnet is lodestone.

The substances which when placed in a magnetic field become strongly magnetized in the direction of the field and retain their magnetization even after the field is removed are called permanent magnets or permanent ferromagnets.

Now, the atoms in a permanent magnet are always in a state of vibrations in random directions. These vibrations are created as a result of energy from normal temperatures. With time, these vibrations change with changes in ambient/room temperature which subsequently randomizes the magnetic domain orientations. (see note 1). This deteriorates the magnetization power of the magnet.

Another reason for a permanent magnet to lose its magnetization with time could be consistent improper handling. Very sharp impacts can jostle the orientation of the atoms in the magnet by sending a shock through the material caused by dropping the magnet or by hitting it with a hammer. Since permanent magnets have no external field to guide the atoms to re-align themselves in the desired orientation, they will align back in random directions which will again reduce the magnetization intensity of the magnet.

So, the correct answer is “Option A”.

Additional Information:
Other reasons for a permanent magnet losing magnetism that are unrelated to time are heat, and exposure to a demagnetizing field.
If a permanent magnet is heated beyond a point called the Curie temperature the heat will permanently disrupt the domain structure of the material and lose most of its magnetization.
If a permanent magnet is exposed to a magnetic field that is sufficiently higher than its coercivity and of an opposite polarity, the magnet will get demagnetized either completely or to an extent, depending on the strength of the field applied

Note:
1) It is important to understand the domain theory of ferromagnets, which suggests that the volume of a ferromagnetic material is made up of small elements called domains, each which contain a certain number of atoms whose magnetic axes are aligned in the same direction even in the absence of any external field. For a permanent (ferro) magnet, the atoms in all domains are aligned in the same direction.
2)Now, in the context of magnetism let us look at a few more terms of importance:
Retentivity is defined as the intensity of magnetization that remains in the material when the magnetizing field is removed.
Coercivity is defined as the amount of magnetizing field intensity that is required to destroy the residual magnetism in the material.
Permeability is defined as the property that allows magnetic field lines to pass through a material, which is nothing but its magnetization capability.
Permanent magnets have a high retentivity, high coercivity and a high permeability.