In a permanent magnet at room temperature.

Options

A. Magnetic moment of each molecule is zero
B. The individual molecules have non-zero magnetic 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 at room temperature retain ferromagnetic property is long period of time.
The individual atoms in a ferromagnetic possess a dipole moment as in a paramagntic. However, they interact with one another in such as that they spontaneously align themselves in a direction over a macroscopic volume. Thus, we can say that in a permanent magnet temperature, domains are all perfectly aligned.