In a permanent magnet at room temperature.

Options

A. Magnetic moment of each molecule is zero
B. The individual molecules have non-zero magnetic moment which are all perfectly aligned
C. Domains are partially aligned
D. Domains are all perfectly aligned

Answer

D

Explanation

As we know a permanent magnet is a substance which at room temperature 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.