In ferromagnetic material what is the size of typical domain and how many numbers of atoms individual domain contain?

Correct option is B

Correct Answer: (b) 1^–2 mm, about 10¹³ atoms
Explanation:
· A typical ferromagnetic domain has a size of about 1^–2 mm, and each domain contains roughly 10¹³ atoms whose magnetic moments align in the same direction.
· This collective alignment gives ferromagnetic materials their strong magnetic properties.
Information Booster:
· Ferromagnetic domains form to minimize the internal energy of the material.
· When an external magnetic field is applied:
· Domains aligned parallel to the field grow larger,
· Oppositely oriented domains shrink,
· Causing the material to become strongly magnetised.
· Domain walls are thin boundaries where atomic magnetic moments gradually shift orientation.