you need
  • physics textbook, paper, pencil.
Read the textbook on physics that creates a magnetic field in the surrounding space.The cause of the magnetic field or that explains its direction.At the micro level magnetic field is generated microcurrent, generated by the movement of electrons around the nucleus.When the orientation of the electron spin becomes the same, the substance is magnetized.In addition, each has its own micro-current magnetic field is determined by the right-hand rule or the rule of thumb.
Draw on a piece of paper solenoid has studied in the school course of physics.As is known, it is a solenoid coil having a magnetic core, either with an empty content.The coil is connected to a DC power source.Ring coil creates its own magnetic field.To determine the d
irection of the field, use the rule of thumb.This rule says that the direction of the solenoid magnetic field coincides with the direction of the translational motion of the handle in a corkscrew if the direction of rotation of the handle coincides with the direction of current in the solenoid coil.
Remember the rule of thumb or the right-hand rule.It is essential for determining the magnetic field direction in most cases.Any arbitrarily complex configuration of the magnetic source object can be divided into the more detailed part of the field which can be determined by the rule of thumb.
Write out a textbook on physics law of Biot-Savart-Laplace.The law allows to calculate the magnitude and direction of the magnetic induction in any general case.The basis for the calculation of the magnetic field of this rule are the currents that create this field.And the length of the areas in which the current flows, can be done arbitrarily small up to elementary values, thus increasing the accuracy of the calculation.