Question

In a permanent magnet at room temperature ______.

Options

• magnetic moment of each molecule is zero.

• the individual molecules have non-zero magnetic moment which are all perfectly aligned.

• domains are partially aligned.

• domains are all perfectly aligned.

Answer 1

In a permanent magnet at room temperature domains are all perfectly aligned.

Explanation:

At room temperature permanent magnet behaves as a ferromagnetic substance for a long period of time.

At room temperature, the permanent magnet retains ferromagnetic property for a long period of time.

The individual atoms in a ferromagnetic material possess a dipole moment as in a paramagnetic material.

However, they interact with one another in such a way that they spontaneously align themselves in a common direction over a macroscopic volume called domain. Thus, we can say that in a permanent magnet at room temperature, domains are all perfectly aligned.