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.
Advice 2 : How to find the magnetic induction vector
To determine the vector of magnetic induction need to know not only its absolute value but also the direction. Absolute value is determined in the measurement of the interaction of bodies through the magnetic field and the direction of the motion of the bodies and special rules.
You will need
- - current source;
- - the solenoid;
- - the right gimlet.
Find the vector of magnetic induction of current-carrying conductor. To do this, connect it to the power source. Flowing a current through a wire by using a tester find its value in amperes. Determine the point where will be measured the magnetic field, from this point drop a perpendicular to the conductor and find its length R. Find the modulus of a vectorand the magnetic induction at a given point. For this purpose, the value of the current I multiply by the magnetic constant μ≈1,26•10^(-6). The result, divide by the length of the perpendicular in meters, and double the number π≈3,14, B=I•μ/(R•2•π). This is the absolute value vectorand the magnetic induction.
To find the direction vectorand the magnetic induction, take the right gimlet. Suitable conventional corkscrew. Position it so that the rod was parallel to the conductor. Start to rotate the thumb so that the rod began to move in the same direction as the current. Rotation of the handle will indicate the direction of magnetic field lines.
Find the vector magnetic induction loop of wire with a current. To do this, measure the amperage in the coil tester and coil radius with the ruler. To find the module of the magnetic induction inside the coil, the current I multiply by the magnetic constant μ≈1,26•10^(-6). The received result divide by twice the radius R, B=I•μ/(2•R).
Determine the direction vectorand the magnetic induction. To do this, the right thumb, install the rod in the center of the loop. Start rotating it in the direction of current in it. Translational movement of the rod will show the direction vectorand the magnetic induction.
Calculate the magnetic induction inside the solenoid. To do this, count the number of turns and length, tentatively Express in meters. Connect the solenoid to the source and tester measure the current. Calculate the magnetic field inside the solenoid by multiplying the current I by the number of turns N and the magnetic constant μ≈1,26•10^(-6). The result, divide by the length of the solenoid L, B=N•I•μ/L. the Direction vectorand the magnetic induction inside the solenoid, determine the same as in the case of one turn of the conductor.