Question

10. State two advantages of an electromagnet over a
permanent magnet.
11. State two differences between an electromagnet and
a permanent magnet.
12. Why is soft iron used as the core of the electromagnet
in an electric bell ?​

Answer 1

Answer:

An electromagnet is simply a coil of wire.  It is usually wound around an iron core.  However, it could be wound around an air core, in which case it is called a solenoid.  When connected to a current source, the electromagnet becomes energized, creating a magnetic field just like a permanent magnet.   The magnetic flux density is proportional to the magnitude of the current flowing in the wire of the electromagnet. 

An electromagnet is simply a coil of wire.  It is usually wound around an iron core.  However, it could be wound around an air core, in which case it is called a solenoid.  When connected to a current source, the electromagnet becomes energized, creating a magnetic field just like a permanent magnet.   The magnetic flux density is proportional to the magnitude of the current flowing in the wire of the electromagnet. Advantages of electromagnet over permanent magnets:

An electromagnet is simply a coil of wire.  It is usually wound around an iron core.  However, it could be wound around an air core, in which case it is called a solenoid.  When connected to a current source, the electromagnet becomes energized, creating a magnetic field just like a permanent magnet.   The magnetic flux density is proportional to the magnitude of the current flowing in the wire of the electromagnet. Advantages of electromagnet over permanent magnets:Electromagnets can be designed to produce particular fields and has a possibility of changing the magnetic field over a period of time. This can be achieved by simply changing the current supplied to the coil, allowing the electromagnet to be switched on and off.The strength of an electromagnet can be adjusted by the amount of electric current allowed to flow into it. As a result, the same electromagnet can be adjusted for different strength levels.If a permanent magnet loses its magnetic properties, as it does by heating to a (maximum) temperature, it will be rendered useless and its magnetic properties can be only recovered by re-magnetizing. Contrarily, an electromagnet loses its magnetic power every time an electric current is removed and becomes magnetic once again when the electric field is introduced.