What method of magnetism is used when a needle is magnetized by holding a magnet near the needle?

What method of magnetism is used when a needle is magnetized by holding a magnet near the needle?

• A. Friction magnetism
• B. Magnetizing by induction
• C. Electrical magnetism
• D. Residual magnetism

Answer: (B)

Magnetizing by induction is at work here. When a magnet is brought close to a needle, its magnetic field interacts with the needle’s magnetic domains. The external field causes those domains to align with the field, so the needle becomes magnetized even though there isn’t any rubbing or electrical current involved. As long as the external magnet is nearby, the alignment remains strong; after the magnet is removed, the needle may keep some of that alignment as residual magnetism, depending on the material. This distinguishes it from friction magnetism (rubbing), electrical magnetism (current-producing a field), or residual magnetism (leftover magnetism from a previous magnetization).

Magnetizing by induction is at work here. When a magnet is brought close to a needle, its magnetic field interacts with the needle’s magnetic domains. The external field causes those domains to align with the field, so the needle becomes magnetized even though there isn’t any rubbing or electrical current involved. As long as the external magnet is nearby, the alignment remains strong; after the magnet is removed, the needle may keep some of that alignment as residual magnetism, depending on the material. This distinguishes it from friction magnetism (rubbing), electrical magnetism (current-producing a field), or residual magnetism (leftover magnetism from a previous magnetization).