Electromagnetism:-

In the previous topic, you learned the very important fact that an electric current can be caused to flow when you move a wire of coil so that it is cutting through a magnetic field.  you also learned that this is a most wide speared manner which electricity is generated for the home, for industry, abroad ship.

Since magnetism can be made to generate electricity, it does not seem too great a jump for the imagination to wonder if electricity can generate a magnetic field. in this topic, you will see for yourself that that is exactly what can be done.

In the last topic, you made use of permanent magnets to caused an electric current to flow.  you saw that more current could be generated as you increase the number of turns of wire, the speed of motion of the coil, and the strength of the magnetic field.it is a simple matter to accomplish the first two of these in a practical electrical generator, but it is very difficult to increase the strength of a permanent magnet beyond certain limits.

In order, the generator is large amounts of electricity much stronger magnetic field must be used. That is accomplished, as will you see in this topic, by means of an electromagnet. an electromagnet work on the simple principle that a magnetic field can be generated by passing an electric current through a coil of wire.

An Electromagnetism field is a magnetic field caused by the current flow in a wire. whenever electric current is flowing, a magnetic field exists around the conductor, and the direction of this magnetic field depends upon the direction of current flows. the illustration shows the conductor carrying current in a different direction.

The direction of a magnetic field is countered clockwise when the current flows from left to right. if the direction of current flow reserves the direction of the magnetic field also reserves, as shown. in the cross-sectional view of the magnetic field around the conductors, the dot in the center of the circle represents the current flowing out of the paper toward you, and the cross represents the current flowing into the paper away from you.

A definite relationship exists between the direction of current flow in the wire and the direction of the magnetic field around the conductors. this relationship can be shown by using the left-hand rules. these rules state that if a current-carrying conductor is grasped in the left hand with the thumb pointing in the direction of the magnetic line force. the illustration shows the application of the left-hand rule to determine the direction of the magnetic field of a conductor.