When a magnetic material like soft iron or a steel paperclip is brought near a strong magnet or placed inside a current-carrying solenoid, it becomes temporarily magnetized through induced magnetism.
Near a Permanent Magnet: As you bring an unmagnetized piece of iron close to the north pole of a permanent magnet, the magnetic field exerts forces on the iron’s internal domains, aligning them. The end closest to the magnet becomes a temporary south pole, while the far end becomes a north pole. Because unlike poles attract, the induced south pole is drawn toward the magnet’s north pole, causing attraction.
Near a Current-Carrying Solenoid: When a magnetic material is placed near a solenoid with electric current, the coil’s magnetic field aligns the domains in the material, effectively turning it into a magnet with its own north and south poles. This induced magnetism strengthens the overall magnetic field of the solenoid.
Magnets can be broadly classified into temporary magnets and permanent magnets. Both produce magnetic fields, but they differ in how they retain their magnetism and how they are used in practical applications.
| Property | Temporary Magnet (e.g. Iron) | Permanent Magnet (e.g. Steel) |
|---|---|---|
| Magnetism Retention | Loses magnetism easily when the magnetic field is removed | Retains magnetism for a long time after being magnetised |
| Magnetic Strength | Can be strong but only while under influence of a magnetic field | Usually not as strong as a temporary magnet initially, but long-lasting |
| Materials | Made from soft magnetic materials like iron | Made from hard magnetic materials like steel, neodymium, or cobalt alloys |
| Ease of Magnetisation | Easy to magnetise | Difficult to magnetise |
| Uses | Electromagnets, temporary lifting devices, relays | Bar magnets, magnetic compasses, refrigerator magnets |