Magnetic induction is vector size, and therefore except an absolute value is characterized by the direction. To find it, it is necessary to find poles of a permanent magnet or the direction of current which generates magnetic field.
It is required to you
- - reference magnet;
- - current source;
- - right gimlet;
- - direct conductor;
- - coil, wire round, solenoid.
Instruction
1. Define the direction of a vector of magnetic induction of a permanent magnet. For this purpose find its North and South Pole. Usually North Pole of a magnet has blue color, and southern to – red. If poles of a magnet are unknown, take a reference magnet and bring it the North Pole to the unknown. That end which will be attracted to the North Pole of a reference magnet will be the South Pole of a magnet which induction of the field is measured. Lines of magnetic induction leave the North Pole and enter the South Pole. The vector in each point of the line goes in the direction of the line on a tangent.
2. Define the direction of a vector of magnetic induction of the direct conductor with current. Current goes from a positive pole of a source to negative. Take the gimlet which is twisted at rotation clockwise, it is called right. Begin to twist it in that direction where there is current at the conductor. Rotation of a handle will show the direction of the closed circular lines of magnetic induction. The vector of magnetic induction will pass in this case on a tangent to a circle.
3. Find the direction of magnetic field of a round with current, the coil or the solenoid. For this purpose connect the conductor to a current source. Take the right gimlet and rotate its handle in the direction of the current going on rounds from a positive pole of a source of current to negative. Progress of a rod of the gimlet will show the direction of power lines of magnetic field. For example, if the handle of the gimlet rotates in the direction of current counterclockwise (to the left), then it, getting out, progressively moves towards the observer. Therefore power lines of magnetic field are directed towards the observer too. In a round, the coil or the solenoid of the line of magnetic field the straight lines, in the direction and an absolute value coincide with a vector of magnetic induction.