| Definition |
Permanent magnets are materials that retain their magnetism for a long time without needing an external magnetic field. |
Temporary magnets are materials that only exhibit magnetic properties when placed in a magnetic field and lose their magnetism once the field is removed. |
| Magnetism |
Permanent magnets have intrinsic magnetism, meaning they are always magnetized. |
Temporary magnets only become magnetized when influenced by an external magnetic field. |
| Types of Materials |
Made from materials such as steel, iron, cobalt, and nickel that retain their magnetic properties over time. |
Made from materials like soft iron or ferromagnetic materials that easily become magnetized in the presence of a magnetic field. |
| Magnetization |
The magnetic properties of a permanent magnet are stable and do not change under normal conditions. |
The magnetization is temporary and can be easily lost when the external field is removed. |
| Duration of Magnetism |
Permanent magnets retain their magnetism for a long time, even indefinitely, unless subjected to extreme conditions like heating or physical impact. |
Temporary magnets only exhibit magnetism while within the external magnetic field. Once the external field is removed, they lose their magnetization. |
| Examples |
Bar magnets, horseshoe magnets, magnetic compass needles, and neodymium magnets. |
Electromagnets, nails magnetized by rubbing, and a piece of iron near a strong magnet. |
| Strength of Magnetism |
Permanent magnets have a strong, constant magnetic field. |
Temporary magnets have a weaker, variable magnetic field that diminishes when the external field is removed. |
| Response to External Fields |
Permanent magnets do not require an external magnetic field to maintain their magnetism. |
Temporary magnets lose their magnetism once the external magnetic field is removed. |
| Applications |
Used in applications where constant magnetic properties are required, such as in motors, generators, magnetic storage devices, and compasses. |
Used in situations where temporary magnetism is needed, such as in electromagnets (used in lifting heavy objects or in electric bells) and magnetic relays. |
| Retentivity |
Permanent magnets have high retentivity, meaning they can retain their magnetism well over time. |
Temporary magnets have low retentivity, meaning they quickly lose their magnetism once the external field is removed. |
| Ease of Magnetization |
Permanent magnets are difficult to magnetize and require a process like heating or applying a strong magnetic field. |
Temporary magnets are easy to magnetize and can be magnetized by placing them in an external magnetic field. |