What are the effects of a magnet on a. an iron nail b. a brass pen?
The correct answer and explanation is:
Correct Answer:
a. An iron nail – The magnet attracts the iron nail.
b. A brass pen – The magnet does not affect the brass pen.
Explanation (300 words):
Magnets exert forces on certain types of materials depending on their magnetic properties. These materials fall into three broad categories: ferromagnetic, paramagnetic, and diamagnetic. The behavior of an object in a magnetic field depends on which category it belongs to.
(a) An iron nail is made of iron, which is a ferromagnetic material. Ferromagnetic materials are strongly attracted to magnets because they have domains (regions with aligned magnetic moments) that can be influenced by external magnetic fields. When a magnet is brought near an iron nail, it aligns the magnetic domains within the nail, causing the nail to become magnetized and stick to the magnet. In some cases, the nail may retain some magnetism even after the external magnet is removed. This strong attraction is why iron objects are commonly used in magnetic experiments and applications.
(b) A brass pen, on the other hand, is made of brass — an alloy of copper and zinc — both of which are non-magnetic (specifically, diamagnetic). Diamagnetic materials create a very weak opposing magnetic field when exposed to a magnet, resulting in no noticeable attraction or repulsion. As a result, the magnet has virtually no effect on the brass pen. It will not be attracted, and it will not move in response to the magnet’s presence.
In summary, the key difference lies in the material’s internal structure and how it responds to a magnetic field. Iron (a ferromagnetic material) is attracted to magnets because of its atomic structure and magnetic domains. Brass, being non-ferromagnetic, shows no significant reaction. This difference in magnetic behavior is essential in various real-world applications, such as designing electric motors, magnetic locks, and selecting materials for shielding or conduction.