a. Insert the iron nail (or soft iron) into the inside of a threaded coil, when the coil is connected to the current, the magnetic field inside the coil will be magnetic and magnetic.

b. The magnetic field generated by the iron nails and the magnetic field in the original coil makes the total magnetic field intensity greatly enhanced.

c. When the current is cut off, the magnetism of the coil and the iron nails disappears immediately. The magnet obtained by this method is called the electromagnet.

d. Enhance the magnetic field method of the thread pipeline coil [1] Increase the number of units [2] Enhance the circular current [3] Put the soft magnet

6. The characteristics of electromagnet

a. Can increase the current and increase the number of coils to make its magnetic force greater than natural magnets. You can hang huge steel plates or abandoned cars. There are also electromagnets in Ampere and Volt.

b. The power generation generates magnetism, and the magnetic disappearance is disappeared when the current stops. It can change the size and direction at will, which is more convenient to use than permanent magnets.