You will need
- the source current (conductor, solenoid);
- - the right hand;
- - magnetic hands.
To find the direction of magnetic lines for a straight conductor with current, position it so that the electric current was in the direction from you (for example, a sheet of paper). Try to remember how to move the drill or screwdriver to tighten the screw clockwise and forward. Draw this gesture in order to understand the direction of the lines. Thus, the magnetic field lines are directed clockwise. Check them schematically in the drawing. This method is called corkscrew rule.
If the handler is not in that direction, mentally stand that way, or rotate the design so that the current from you was removed. Then, remember the movement of the drill or screw and set the direction of the magnetic lines in a clockwise direction.
If the rule of thumb seems to be difficult, try using the right hand rule. In order to determine the direction of magnetic lines, place a hand use your right hand with protruding thumb. The thumb channel on the movement of the conductor, and the remaining 4 fingers in the direction of the induced current. Now please note, the magnetic field lines enter the palm of your hand.
In order to use the right hand rule for coils with current grasp it mentally palm of his right hand so that the fingers pointing along the current in the coils. View, which looks set aside the thumb is the direction of the magnetic lines inside the solenoid. This method will help to determine the orientation of metal bars, if you need to charge a magnet with a coil with a current.
To determine the direction of magnetic lines with the help of the magnetic needle, place a few of these arrows around the wire or coil. You will see that the axis of the arrows is directed along the tangents to the circle. Using this method it is possible to find the direction lines at each point of space and to prove their continuity.