It is not all the metal materials can be a magnet. There are three categories of metal, respectively, are:
- Ferromagnetic material, He is the type of metal that is very easily made into objects of magnets and magnet very easily influenced. Materials of this type, such as iron, steel, and nickel
- The magnetic material, He is the kind of metal that can not be made into magnetic objects but can still be influenced by magnets. Materials of this type such as platinum and manganese.
- Magnetic Materials him, He is the kind of metal that can not be made magnet and also can not be affected by the magnet. Materials of this type such as silicon, copper, zinc, gold.
Magnetic field lines
Move the needle magnet (can use a small compass) starting from the end of the bar magnet, and then towards the end of the circular magnet to another. Note the appointment of a magnetic needle. Magnet Needle changed as Figure 1.106 below.
Image 1106 Trial magnetic field lines
Graphically, the magnetic field is described as Figure 1107, where the magnetic field lines always form a closed circle.
Use of Permanent Magnet
The permanent magnet is used to generate mechanical power, to change menkanik energy into electrical energy and to convert electrical energy into mechanical energy. In a generator, if we move the copper wire in a magnetic field, it will terbangkit electrical energy. This effect is also used in the microphone, where the membrane associated with the coil, the coil when it moves it will terbangkit large electricity with appropriate sound on the membrane.
In the motor, when the copper wire in a magnetic field electrified, then there will be movement. When this movement will be converted into rounds. In this second effect can also be used on stationery pointer on the measuring instrument. Also used also in loudspeaker, where the movement of the wire will move the membrane.