DETERMINING THE DIRECTION OF MAGNETIC FIELD LINES
GILMET RULE
for a straight conductor with current
— serves to determine the direction of magnetic lines (magnetic induction lines)
around a straight conductor carrying current.
If the direction of translational movement of the gimlet coincides with the direction of the current in the conductor, then the direction of rotation of the gimlet handle coincides with the direction of the magnetic field lines of the current.
Let's say the current-carrying conductor is located perpendicular to the plane of the sheet:
1. direction email. current from us (into the plane of the sheet)
According to the gimlet rule, the magnetic field lines will be directed clockwise.
Then, according to the gimlet rule, the magnetic field lines will be directed counterclockwise.
RIGHT HAND RULE
for a solenoid (i.e. a coil with current)
- serves to determine the direction of magnetic lines (magnetic induction lines) inside the solenoid.
If you clasp the solenoid with the palm of your right hand so that four fingers are directed along the current in the turns, then the extended thumb will show the direction of the magnetic field lines inside the solenoid.
1. How do 2 coils with current interact with each other? 
2. How are the currents in the wires directed if the interaction forces are directed as in the figure?
3. Two conductors are parallel to each other. Indicate the direction of the current in the LED conductor.
I'm looking forward to solutions at the next lesson at "5"!
It is known that superconductors (substances that have practically zero electrical resistance at certain temperatures) can create very strong magnetic fields. Experiments have been carried out to demonstrate similar magnetic fields. After cooling the ceramic superconductor with liquid nitrogen, a small magnet was placed on its surface. The repulsive force of the superconductor's magnetic field was so high that the magnet rose, hovered in the air and hovered over the superconductor until the superconductor, heating up, lost its extraordinary properties.
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A MAGNETIC FIELD
- this is a special type of matter through which interaction between moving electrically charged particles occurs.
PROPERTIES OF (STATIONARY) MAGNETIC FIELD
Permanent (or stationary) A magnetic field is a magnetic field that does not change over time.
1. Magnetic field is created moving charged particles and bodies, current-carrying conductors, permanent magnets.
2. Magnetic field valid on moving charged particles and bodies, on conductors with current, on permanent magnets, on a frame with current.
3. Magnetic field vortex, i.e. has no source.
- these are the forces with which current-carrying conductors act on each other.
. 
is the strength characteristic of the magnetic field.
The magnetic induction vector is always directed in the same way as a freely rotating magnetic needle is oriented in a magnetic field.
SI unit of magnetic induction:
MAGNETIC INDUCTION LINES
- these are lines tangent to which at any point is the magnetic induction vector.
Uniform magnetic field- this is a magnetic field in which at any point the magnetic induction vector is constant in magnitude and direction; observed between the plates of a flat capacitor, inside a solenoid (if its diameter is much smaller than its length) or inside a strip magnet.
Magnetic field of a straight conductor carrying current:
where is the direction of the current in the conductor towards us perpendicular to the plane of the sheet,
- the direction of the current in the conductor away from us is perpendicular to the plane of the sheet.
Solenoid magnetic field:
Magnetic field of a strip magnet:
- similar to the magnetic field of a solenoid.
PROPERTIES OF MAGNETIC INDUCTION LINES
- have a direction;
- continuous;
-closed (i.e. the magnetic field is vortex);
- do not intersect;
— their density is used to judge the magnitude of magnetic induction.
DIRECTION OF MAGNETIC INDUCTION LINES
- determined by the gimlet rule or the right hand rule.
Gimlet rule (mostly for a straight conductor carrying current):
Right hand rule (mainly for determining the direction of magnetic lines
inside the solenoid):
There are other possible applications of the gimlet and right hand rules.
is the force with which a magnetic field acts on a current-carrying conductor.
The ampere force module is equal to the product of the current strength in the conductor by the magnitude of the magnetic induction vector, the length of the conductor and the sine of the angle between the magnetic induction vector and the direction of the current in the conductor.
The Ampere force is maximum if the magnetic induction vector is perpendicular to the conductor.
If the magnetic induction vector is parallel to the conductor, then the magnetic field has no effect on the current-carrying conductor, i.e. Ampere's force is zero.
The direction of the Ampere force is determined by left hand rule:
If the left hand is positioned so that the component of the magnetic induction vector perpendicular to the conductor enters the palm, and 4 extended fingers are directed in the direction of the current, then the thumb bent 90 degrees will show the direction of the force acting on the current-carrying conductor.
or 
EFFECT OF MAGNETIC FIELD ON A FRAME WITH CURRENT
A uniform magnetic field orients the frame (i.e., a torque is created and the frame rotates to a position where the magnetic induction vector is perpendicular to the plane of the frame).
A non-uniform magnetic field orients + attracts or repels the current-carrying frame.
Thus, in the magnetic field of a straight conductor with current (it is non-uniform), the frame with current is oriented along the radius of the magnetic line and is attracted or repelled from the straight conductor with current, depending on the direction of the currents.
Remember the topic “Electromagnetic phenomena” for 8th grade:
Right hand rule
When a conductor moves in a magnetic field, a directed movement of electrons is created in it, that is, an electric current, which is due to the phenomenon of electromagnetic induction.
For determining direction of electron movement Let's use the left-hand rule we know.
If, for example, a conductor located perpendicular to the drawing (Figure 1) moves along with the electrons it contains from top to bottom, then this movement of electrons will be equivalent to an electric current directed from bottom to top. If the magnetic field in which the conductor moves is directed from left to right, then to determine the direction of the force acting on the electrons, we will have to place our left hand with the palm to the left so that the magnetic lines of force enter the palm, and with four fingers up (against the direction of movement conductor, i.e. in the direction of the “current”); then the direction of the thumb will show us that the electrons in the conductor will be acted upon by a force directed from us to the drawing. Consequently, the movement of electrons will occur along the conductor, i.e., from us to the drawing, and the induction current in the conductor will be directed from the drawing to us.
Picture 1. The mechanism of electromagnetic induction. By moving a conductor, we move along with the conductor all the electrons contained in it, and when moving electric charges in a magnetic field, a force will act on them according to the left-hand rule.
However, the left-hand rule, which we applied only to explain the phenomenon of electromagnetic induction, turns out to be inconvenient in practice. In practice, the direction of the induction current is determined according to the right hand rule(Figure 2).
Figure 2. Right hand rule. The right hand is turned with the palm towards the magnetic lines of force, the thumb is directed in the direction of movement of the conductor, and four fingers indicate in which direction the induced current will flow.
Right hand rule is that, if you place your right hand in a magnetic field so that the magnetic lines of force enter the palm, and the thumb indicates the direction of movement of the conductor, then the other four fingers will show the direction of the induced current arising in the conductor.
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A simple explanation of the gimlet rule
Explanation of the name
Most people remember mention of this from a physics course, namely the electrodynamics section. This happened for a reason, because this mnemonic is often given to students to simplify their understanding of the material. In fact, the gimlet rule is used both in electricity, to determine the direction of the magnetic field, and in other sections, for example, to determine angular velocity.
A gimlet is a tool for drilling small-diameter holes in soft materials; for a modern person, it would be more common to use a corkscrew as an example.
Important! It is assumed that the gimlet, screw or corkscrew has a right-hand thread, that is, the direction of its rotation when tightened is clockwise, i.e. to the right.
The video below provides the full formulation of the gimlet rule, be sure to watch it to understand the whole point:
How is the magnetic field related to the gimlet and hands?
In physics problems, when studying electrical quantities, one is often faced with the need to find the direction of the current from the magnetic induction vector and vice versa. These skills will also be required when solving complex problems and calculations involving magnetic field systems.
Before we begin to consider the rules, I want to remind you that current flows from a point with a higher potential to a point with a lower one. It can be said more simply - the current flows from plus to minus.
The gimlet rule has the following meaning: when the tip of the gimlet is screwed in along the direction of the current, the handle will rotate in the direction of vector B (the vector of magnetic induction lines).
The right hand rule works like this:
Place your thumb as if you were showing “cool!”, then turn your hand so that the direction of the current and the finger coincide. Then the remaining four fingers will coincide with the magnetic field vector.
A visual analysis of the right hand rule:
To see this more clearly, conduct an experiment - scatter metal shavings on paper, make a hole in the sheet and thread a wire, after applying current to it, you will see that the shavings will group into concentric circles.
Magnetic field in a solenoid
All of the above is true for a straight conductor, but what if the conductor is wound into a coil?
We already know that when current flows around a conductor, a magnetic field is created, a coil is a wire coiled into rings around a core or mandrel many times. The magnetic field in this case increases. The solenoid and the coil are, in principle, the same thing. The main feature is that the magnetic field lines run in the same way as in the situation with a permanent magnet. The solenoid is a controlled analogue of the latter.
The right hand rule for the solenoid (coil) will help us determine the direction of the magnetic field. If you hold the coil in your hand with four fingers facing in the direction the current is flowing, then your thumb will point to vector B in the middle of the coil.
If you twist a gimlet along the turns, again in the direction of the current, i.e. from the “+” terminal to the “-” terminal of the solenoid, then the sharp end and the direction of movement correspond to the magnetic induction vector.
In simple words, wherever you twist the gimlet, the magnetic field lines come out. The same is true for one turn (circular conductor)
Determining the direction of current with a gimlet
If you know the direction of vector B - magnetic induction, you can easily apply this rule. Mentally move the gimlet along the direction of the field in the coil with the sharp part forward, respectively, clockwise rotation along the axis of movement will show where the current flows.
If the conductor is straight, rotate the corkscrew handle along the indicated vector, so that this movement is clockwise. Knowing that it has a right-hand thread - the direction in which it is screwed in coincides with the current.
What is connected with the left hand
Do not confuse the gimlet and the left hand rule; it is needed to determine the force acting on the conductor. The straightened palm of the left hand is located along the conductor. The fingers point in the direction of the flow of current I. Field lines pass through the open palm. The thumb coincides with the force vector - this is the meaning of the left hand rule. This force is called the Ampere force.
You can apply this rule to an individual charged particle and determine the direction of the 2 forces:
Imagine that a positively charged particle is moving in a magnetic field. The lines of the magnetic induction vector are perpendicular to the direction of its movement. You need to place your open left palm with your fingers in the direction of the movement of the charge, vector B should penetrate the palm, then the thumb will indicate the direction of vector Fa. If the particle is negative, the fingers point against the direction of the charge.
If any point was unclear to you, the video clearly shows how to use the left-hand rule:
It is important to know! If you have a body and a force acts on it that tends to turn it, turn the screw in this direction and you will determine where the moment of force is directed. If we are talking about angular velocity, then the situation here is like this: when the corkscrew rotates in the same direction as the rotation of the body, it will screw in the direction of the angular velocity.
It is very simple to master these methods of determining the direction of forces and fields. Such mnemonic rules in electricity greatly facilitate the tasks of schoolchildren and students. Even a full teapot can deal with a gimlet if he has opened wine with a corkscrew at least once. The main thing is not to forget where the current flows. I repeat that the use of a gimlet and the right hand is most often successfully used in electrical engineering.
You probably don't know:
Left and Right Hand Rules
The right hand rule is a rule used to determine the vector of magnetic field induction.
This rule is also called the “gimlet rule” and “screw rule”, due to the similarity of the operating principle. It is widely used in physics, as it allows one to determine the most important parameters - angular velocity, moment of force, angular momentum - without the use of special instruments or calculations. In electrodynamics, this method allows you to determine the vector of magnetic induction. 
Gimlet rule
Rule of the gimlet or screw: if the palm of the right hand is placed so that it coincides with the direction of the current in the conductor under study, then the forward rotation of the handle of the gimlet (thumb of the palm) will directly indicate the vector of magnetic induction.
In other words, you need to screw in a drill or a corkscrew with your right hand to determine the vector. There are no particular difficulties in mastering this rule.
There is another variation of this rule. Most often, this method is simply called the “right-hand rule.”
It sounds like this: to determine the direction of the induction lines of the created magnetic field, you need to take the conductor with your hand so that your thumb left at 90 degrees shows the direction of the current flowing through it. 
There is a similar option for the solenoid.
In this case, you should grasp the device so that the fingers of your palm coincide with the direction of the current in the turns. The protruding thumb in this case will show where the magnetic field lines come from.
Right hand rule for moving conductor
This rule will also help in the case of conductors moving in a magnetic field. Only here you need to act a little differently.
The open palm of the right hand should be positioned so that the field lines enter it perpendicularly. The extended thumb should point in the direction of movement of the conductor. With this arrangement, the extended fingers will coincide with the direction of the induction current.
As we can see, the number of situations where this rule really helps is quite large.
First rule of the left hand
It is necessary to place the left palm in such a way that the field induction lines enter it at a right angle (perpendicular). The four outstretched fingers of the palm should coincide with the direction of the electric current in the conductor. In this case, the extended thumb of the left palm will show the direction of the force acting on the conductor. 
In practice, this method allows you to determine the direction in which a conductor with an electric current passing through it, placed between two magnets, will begin to deviate.
Second rule of the left hand
There are other situations where you can use the left-hand rule. In particular, to determine the forces with a moving charge and a stationary magnet.
Another left hand rule says: The palm of the left hand should be positioned so that the induction lines of the created magnetic field enter it perpendicularly. The position of the four extended fingers depends on the direction of the electric current (along the movement of positively charged particles, or against negative ones). The protruding thumb of the left hand in this case will indicate the direction of the Ampere force or the Lorentz force.
The advantages of the right and left hand rules are precisely that they are simple and allow you to accurately determine important parameters without the use of additional instruments. They are used both in conducting various experiments and tests, and in practice when it comes to conductors and electromagnetic fields.
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Left hand rule
Straight wire with current. Current (I) flowing through a wire creates a magnetic field (B) around the wire.
Right hand rule
Gimlet rule: “If the direction of translational movement of a gimlet (screw) with a right-hand thread coincides with the direction of the current in the conductor, then the direction of rotation of the gimlet handle coincides with the direction of the magnetic induction vector.”
Determining the direction of the magnetic field around a conductor
Right hand rule: “If the thumb of the right hand is positioned in the direction of the current, then the direction of clasping the conductor with four fingers will show the direction of the lines of magnetic induction.”
For solenoid it is formulated as follows: “If you clasp the solenoid with the palm of your right hand so that four fingers are directed along the current in the turns, then the extended thumb will show the direction of the magnetic field lines inside the solenoid.”
Left hand rule
To determine the direction of the Ampere force is usually used left hand rule: “If you position your left hand so that the induction lines enter the palm, and the outstretched fingers are directed along the current, then the abducted thumb will indicate the direction of the force acting on the conductor.”
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See what the “Left Hand Rule” is in other dictionaries:
LEFT HAND RULE, see FLEMING'S RULES... Scientific and technical encyclopedic dictionary
left hand rule- - [Ya.N.Luginsky, M.S.Fezi Zhilinskaya, Yu.S.Kabirov. English-Russian dictionary of electrical engineering and power engineering, Moscow, 1999] Topics of electrical engineering, basic concepts EN Fleming s ruleleft hand ruleMaxwell s rule ... Technical Translator's Guide
left hand rule- kairės rankos taisyklė statusas T sritis fizika atitikmenys: engl. Fleming's rule; left hand rule vok. Linke Hand Regel, f rus. left hand rule, n; Fleming's rule, n pranc. règle de la main gauche, f … Fizikos terminų žodynas
Straight wire with current. Current (I) flowing through a wire creates a magnetic field (B) around the wire. The gimlet rule (also the right hand rule) is a mnemonic rule for determining the direction of the angular velocity vector characterizing the speed ... Wikipedia
Jarg. school Joking. 1. Left hand rule. 2. Any unlearned rule. (Recorded 2003) ... Large dictionary of Russian sayings
Determines the direction of the force that acts on a current-carrying conductor located in a magnetic field. If the palm of the left hand is positioned so that the extended fingers are directed along the current, and the magnetic field lines enter the palm, then... ... Big Encyclopedic Dictionary
To determine the direction of mechanical forces, to paradise acts on those located in the magnet. field conductor with current: if you position your left palm so that the outstretched fingers coincide with the direction of the current, and the magnetic field lines. fields entered the palm, then... ... Physical encyclopedia
Thanks to today's video tutorial, we will learn how a magnetic field is detected by its effect on an electric current. Let's remember the rule of the left hand. Through experiment we will learn how a magnetic field is detected by its effect on another electric current. Let's study what the left hand rule is.
In this lesson, we will discuss the issue of detecting a magnetic field by its effect on an electric current, and get acquainted with the left-hand rule.
Let's turn to experience. The first such experiment to study the interaction of currents was carried out by the French scientist Ampere in 1820. The experiment was as follows: an electric current was passed through parallel conductors in one direction, then the interaction of these conductors was observed in different directions.
Rice. 1. Ampere's experiment. Co-directional conductors carrying current attract, opposite conductors repel
If you take two parallel conductors through which electric current passes in the same direction, then in this case the conductors will attract each other. When electric current flows in different directions in the same conductors, the conductors repel each other. Thus, we observe the force effect of a magnetic field on an electric current. So, we can say the following: a magnetic field is created by an electric current and is detected by its effect on another electric current (Ampere's force).
When a large number of similar experiments were carried out, a rule was obtained that relates the direction of magnetic lines, the direction of electric current and the force action of the magnetic field. This rule is called left hand rule. Definition: the left hand must be positioned so that the magnetic lines enter the palm, four extended fingers indicate the direction of the electric current - then the bent thumb will indicate the direction of the magnetic field.
Rice. 2. Left hand rule
Please note: we cannot say that wherever the magnetic line is directed, the magnetic field acts there. Here the relationship between quantities is somewhat more complicated, so we use left hand rule.
Let us remember that electric current is the directional movement of electric charges. This means that a magnetic field acts on a moving charge. And in this case we can also use the left-hand rule to determine the direction of this action.
Take a look at the picture below for different uses of the left-hand rule, and analyze each case yourself.
Rice. 3. Various applications of the left-hand rule
Finally, one more important fact. If the electric current or the speed of a charged particle is directed along the magnetic field lines, then there will be no effect of the magnetic field on these objects.
List of additional literature:
Aslamazov L.G. Movement of charged particles in electric and magnetic fields // Quantum. - 1984. - No. 4. - P. 24-25. Myakishev G.Ya. How does an electric motor work? // Quantum. - 1987. - No. 5. - P. 39-41. Elementary physics textbook. Ed. G.S. Landsberg. T. 2. - M., 1974. Yavorsky B.M., Pinsky A.A. Fundamentals of Physics. T.2. - M.: Fizmatlit, 2003.
From experimental physics classes, we can conclude that a magnetic field affects charged particles in motion, and, consequently, current-carrying conductors. The force of a magnetic field acting on a current-carrying conductor is called the Ampere force, and its vector direction establishes the left-hand rule.
Ampere's force is directly proportional to the induction of the magnetic field, the current strength in the conductor, the length of the conductor and the angle of the magnetic field vector relative to the conductor. The mathematical writing of this relationship is called Ampere's law:
F A =B*I*l*sinα
Based on this formula, we can conclude that at α=0° (parallel position of the conductor) the force F A will be zero, and at α=90° (perpendicular direction of the conductor) it will be maximum.
The properties of the force acting on a conductor with an electric current in a magnetic field were described in detail in the works of A. Ampere.
If the Ampere force acts on the entire conductor with a passing current (flow of charged particles), then an individual moving positively charged particle is under the influence of the Lorentz force. The Lorentz force can be expressed through F A by dividing this value by the number of moving charges inside the conductor (concentration of charge carriers).
In a magnetic field, under the influence of the Lorentz force, the charge moves in a circle, provided that the direction of its movement is perpendicular to the induction lines.
The Lorentz force is calculated using the following formula:
F L =q*v*B*sinα
Having carried out a series of physical experiments using magnetic poles as a source of a uniform magnetic field. and frames with current, one can observe a change in the behavior of the frame (it is pushed or pulled into the zone of propagation of the magnetic field) when not only the direction of charged particles changes, but also when the orientation of the poles changes. Thus, the magnetic induction vector, the velocity vector of charged particles (current direction) and the force vector are in close interaction and are mutually perpendicular.
To determine the direction of work of the Lorentz and Ampere forces, you should use the rule of the left hand: “If the palm of the left hand is rotated so that the magnetic field lines enter it at right angles, and the outstretched fingers are located in the direction of the electric current (the direction of movement of particles with a positive charge) , then the direction of the force will be indicated by the perpendicularly moved thumb.”
This simplified formulation allows you to quickly and accurately determine the direction of any unknown vector: force, current or magnetic field induction lines.
The left hand rule applies when:
- the direction of the force on positively charged particles is determined (for negatively charged particles the direction will be opposite);
- the magnetic field induction lines and the velocity vector of charged particles form an angle different from zero (otherwise the force will not act on the conductor).
In a uniform magnetic field, the current-carrying frame is positioned so that the magnetic field lines pass through its plane at right angles.
If a magnetic field is formed around a linear conductor with current, then it is considered inhomogeneous (variable in time and space). In such a field, the current-carrying frame will not only be oriented in a certain way, but will also be attracted to the current-carrying conductor or pushed beyond the limits of the magnetic field. The behavior of the frame is determined by the direction of the currents in the conductor and the frame. The frame with current always rotates along the radius of the induction lines of the inhomogeneous magnetic field.
If we consider two conductors with currents moving in the same direction, then using the left hand rule we can establish that the force acting on the right conductor will be directed to the left, while the force acting on the left conductor will be directed to the right. Consequently, it turns out that the forces acting on the conductors are directed towards each other. It is this conclusion that explains the attraction of conductors with unidirectional currents.
If the current in two parallel conductors flows in opposite directions, then the acting forces will be directed in different directions. This will cause the two conductors to repel each other.
A current-carrying frame placed in a non-uniform magnetic field is subjected to forces in different directions, causing it to rotate. The operating principle of the electric motor is based on this phenomenon.
The application of the left-hand rule is of great practical importance and is the result of repeated experiments that reveal the nature of the magnetic field.
Video about the left hand rule
Using the rules of the left and right hands, you can easily find and determine the directions of current, magnetic lines, and other physical quantities.
Gimlet and right hand rule
The gimlet rule was first formulated by the famous physicist Peter Buravchik. It is convenient to use to determine the direction of tension. So, the formulation of the rule is as follows: in the case when a gimlet, moving translationally, is screwed in the direction of the electric current, the direction of the handle of the gimlet itself must coincide with the direction of the magnetic field. This rule can be applied with a solenoid: we grasp the solenoid, our fingers should point in the same direction as the current, that is, show the path of the current in the turns, then we stick out the thumb of our right hand, it points to the desired path of the magnetic induction lines.
The rule of the right hand is used according to statistics much more often than the rule of the gimlet, partly due to a more understandable formulation, it says: we grasp the object with our right hand, while the clenched fingers of the fist should show the direction of the magnetic lines, and the thumb protruded approximately 90 degrees should show the direction electric current. If there is a moving conductor: the hand should be turned so that the lines of force of this field are perpendicular to the palm (90 degrees), the protruding thumb should point to the path of movement of the conductor, then 4 bent fingers will point to the path of the induction current.
Left hand rule
The left-hand rule has two formulations. The first formulation states: the hand should be positioned so that the remaining curled fingers of the hand indicate the path of electric current in a given conductor, the induction lines should be perpendicular to the palm, and the extended thumb of the left hand indicates the force exerted on a given conductor. The following formulation reads: the four bent fingers of the hand, in addition to the thumb, are located precisely according to the movement of negatively charged or positively charged electric current, and the induction lines should be directed perpendicularly (90 degrees) into the palm, in this case, the exposed thumb in this case should point to the flow Ampere forces or Lorentz forces.