Question

A sample of a ferromagnetic iron in the shape of a cube of side 1.0 μm contains $8.7 \times 10^{29}$ atoms per cubic meter and the magnetic dipole moment of each iron atom is $9.3 \times 10^{-29}$ Am². Then the maximum possible magnetic dipole moment (in Am²) of the sample is nearly

• A. $8.1 \times 10^{-12}$
• B. $8.1 \times 10^{-14}$
• C. $8.1 \times 10^{-16}$
• D. $8.1 \times 10^{-18}$

Hint:

For magnetic dipole moments, ensure you're using the correct number of atoms and magnetic moment per atom when calculating the total.

Answer 1

The Correct Option is A

The maximum possible magnetic dipole moment of the sample is given by: $$ M = N \times m $$ where $N$ is the number of atoms and $m$ is the magnetic dipole moment of each atom. Substituting the values: $$ M = 8.7 \times 10^{29} \times 9.3 \times 10^{-29} = 8.1 \times 10^{-12} \, \text{Am²} $$