3. The magnetic field is the area around a magnet in which there is magnetic force.
(1) Single touch method (2) Double touch method (3) Using electric current.
4. The difference between a permanent magnet and a temporary magnet is in their atomic structures. Permanent magnets have their atoms aligned all the time. Temporary magnets have their atoms aligned only while under the influence of a strong external magnetic field.
Electromagnets are temporary and artificial magnets. They are magnets that are only magnetic when there is a coil of wire with electricity running through it.
Motors and generators, Transformers, Relays, Electric bells and buzzers, Loudspeakers and headphones, Actuators such as valves, Magnetic recording and data storage equipment: tape recorders, VCRs, hard disks, MRI machines etc. (there is a lot)
