Physics teacher Koval V.S. 2010 website

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test work

1. When electric charges are at rest, then around them is found ... A. Electric field. B. Magnetic field. B. electric and magnetic fields. 2. How are iron filings arranged in a direct current magnetic field? A. Disorderly. B. In straight lines along the conductor. B. On closed curves covering the conductor. 3. When one of the poles of a permanent magnet was brought to the magnetic needle, the south pole of the arrow was repelled. Which pole was raised? A. Severny. B. South.

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test work

4. How can the magnetic field of the coil be increased? A. Make a coil of a larger diameter. B. Insert an iron core inside the coil. B. Increase the current in the coil. 5. Which of the following substances is not attracted by a magnet at all? A. Glass. V. Nickel. B. Steel. G. Cast iron 6. The middle of the magnet does not attract iron filings The magnet is broken into two parts .. Will the ends at the place of the break of the magnet attract iron filings? A. They will, but very weakly. B. They won't.

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Detection of a magnetic field by its effect on an electric current. Left hand rule.

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A current-carrying conductor placed in a magnetic field is subjected to a force from the magnetic field.

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The LEFT-HAND RULE for a current-carrying conductor is used to determine the direction of the force acting on a current-carrying conductor in a magnetic field

If the LEFT HAND is positioned so that the lines of the magnetic field enter the palm perpendicular to it, and four fingers are directed along the current, then set aside by 90 degrees thumb shows the direction of the force acting on the conductor.

Slide 7

LEFT HAND RULE for a charged particle in order to determine the direction of the force acting on a single charged particle moving in a magnetic field.

If the LEFT HAND is positioned so that the lines of the magnetic field enter the palm perpendicular to it, and four fingers are directed along the movement of a positively charged particle (or against the movement of a negatively charged particle), then the thumb set aside by 90 degrees will show the direction of the force acting on the particle.

Slide 8

Anchoring

Determine the direction of the force acting on the conductor with current from the magnetic field

Slide 9

In which direction will an electron be deflected by a magnetic field?

Slides captions:

magnetic field and its graphic image
Since electric current is the directed movement of charged particles, we can say that the magnetic field is created by moving charged particles, both positive and negative. For a visual representation of the magnetic field, we used magnetic lines. Magnetic lines are imaginary lines along which small magnetic needles would be placed in a magnetic field. The figure shows a magnetic line (both rectilinear and curvilinear). According to the pattern of magnetic lines, one can judge not only the direction, but also the magnitude of the magnetic field.
Inhomogeneous and uniform magnetic field
The force with which the field of a strip magnet acts on a magnetic needle placed in this field can be different both in absolute value and in direction at different points of the field. Such a field is called inhomogeneous. The lines of an inhomogeneous magnetic field are curved, their density varies from point to point. In some limited area space, you can create a uniform magnetic field, i.e. field, at any point in which the force acting on the magnetic needle is the same in magnitude and direction. For the image of the magnetic field, the following method is used. If the lines of a uniform magnetic field are located perpendicular to the plane of the drawing and are welded from us behind the drawing, then they are depicted with crosses, and if because of the drawing towards us, then with dots.
gimlet rule
The direction of the current magnetic field lines is related to the direction of the current in the conductor. Rule of the gimlet If the direction of the 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 lines of the magnetic field of the current. Using the gimlet rule, in the direction of the current, you can determine the directions of the lines of the magnetic field created by this current, and in the direction of the lines of the magnetic field, the direction of the current that creates this field.
The current-carrying conductor is located perpendicular to the plane of the sheet:
The magnetic field lines will be directed clockwise
The conductor with current is located perpendicular to the plane of the sheet:
The magnetic field lines will be directed counterclockwise
rule right hand
To determine the direction of the magnetic field lines of a solenoid, it is more convenient to use another rule, which is sometimes called the right hand rule. if you clasp the solenoid with the palm of your right hand, pointing four fingers in the direction of the current in the turns, then the retracted thumb will show the direction of the magnetic field lines inside the solenoid.
A solenoid, like a magnet, has poles: the end of the solenoid from which the magnetic lines exit is called the north pole, and the one into which they enter is called the south. Knowing the direction of the current in the solenoid, according to the right-hand rule, you can determine the direction of the magnetic lines inside it, and hence its magnetic poles, and vice versa. The right hand rule can also be used to determine the direction of the magnetic field lines in the center of a single current carrying coil.
Right hand rule for a conductor with current
If the right hand is positioned so that the thumb is directed along the current, then the remaining four fingers will show the direction of the line of magnetic induction
1. A magnetic field is created ... 2. What does the picture of magnetic lines show? 3. Give a characteristic of a uniform magnetic field. Execute drawing.4. Give a characteristic of a non-uniform magnetic field. Execute the drawing. 5. Draw a uniform magnetic field depending on the direction of the magnetic lines. Explain.6. Explain the principle of the gimlet rule.7. Specify two cases where the direction of magnetic lines depends on the direction of electric current.8. What rule should be used to determine the direction of the magnetic lines of the solenoid. What is it?9. How to determine the poles of a solenoid?
Detection of a magnetic field by its effect on an electric current. Left hand rule.
For any conductor with current placed in a magnetic field and not coinciding with its magnetic lines, this field acts with some force.
Conclusions:
A magnetic field is created by an electric current and is detected by its action on an electric current. The direction of the current in the conductor, the direction of the lines of the magnetic field and the direction of the force acting on the conductor are interconnected.
left hand rule

The direction of the force acting on a current-carrying conductor in a magnetic field can be determined using the left hand rule. If left hand arrange so that the lines of the magnetic field enter the palm perpendicular to it, and four fingers are directed along the current. Then the thumb set aside by 900 will show the direction of the force acting on the conductor.
For the direction of the current in the external circuit, the direction from "+" to "-" is taken, i.e. against the direction of movement of electrons in the circuit
Determining the strength of Ampere
If the left hand is positioned so that the magnetic induction vector enters the palm, and the outstretched fingers are directed along the current, then the retracted thumb will indicate the direction of the Ampère force on the conductor with current.
The left hand rule can be used to determine the direction of the force with which a magnetic field acts on individual moving charged particles.
Force acting on a charge
If the left hand is positioned so that the lines of the magnetic field enter the palm perpendicular to it, and four fingers are directed along the movement of a positively charged particle (or against the movement of a negatively charged one), then the thumb set aside by 900 will show the direction of the Lorentz force acting on the particle.
Using the left hand rule, you can determine the direction of the current, the direction of the magnetic lines, the sign of the charge of a moving particle.
The case when the force of the magnetic field on a current-carrying conductor or a moving charged particle F=0
Solve the problem:
A negatively charged particle moving at a speed v in a magnetic field. Make the same drawing in your notebook and indicate with an arrow the direction of the force with which the field acts on the particle. The magnetic field acts with force F on a particle moving at a speed v. Determine the sign of the charge of the particle.

presentation on the topic: "Rule of the left hand. The power of Ampere"

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Lesson in grade 9 on the topic:“Detection of a magnetic field by its effect on an electric current. Left hand rule.Amp power».

Lesson Objectives:

Educational:

study how a magnetic field is detected by its effect on an electric current, study the left hand rule, repeat the previously passed definitions of an electric field, a magnetic field, the conditions for their occurrence, properties; consolidate the rules of the right and left hands with the help of exercises;

consolidate knowledge on previous topics;

to teach how to apply the knowledge gained in the lesson;

show connection with life;

expand interdisciplinary connections.

Educational:

to form interest in the subject, to study, to cultivate initiative, a creative attitude, to cultivate a conscientious attitude to learning, to instill skills, how independent work, and work in a team, to educate the cognitive need and interest in the subject.

Educational:

develop the physical thinking of students, their Creative skills, the ability to independently formulate conclusions, expand cognitive interest by attracting additional material, as well as the need to deepen and expand knowledge;

develop speech skills;

to form the ability to highlight the main thing, draw conclusions, develop the ability to quickly perceive information and perform the necessary tasks; develop logical thinking and attention, the ability to analyze, compare the results obtained, draw appropriate conclusions.

Lesson steps:

1. Organizational moment - 2 minutes.
2. Verification homework, knowledge and skills - 6 min.
3. Explanation of new material - 18 min.
4. Fixing. Problem solving - 15 min.
5. Results. Conclusions. Homework - 4 min.

DURING THE CLASSES

I . Checking homework, knowledge and skills - 6 min

Slide 2.

1. The magnetic field is generated by ______________ (electric current).

2. The magnetic field is created by ______________ charged particles (moving).

3. For the direction of the magnetic line at any of its points, they conditionally take the direction that indicates the _________ pole of the magnetic needle placed at this point (northern).
4. The magnetic lines exit the _________ pole of the magnet and enter _______. (Northern, southern).

They exchanged papers and checked each other. The correct answers are displayed on the screen.

Slide 3.

Correct answers: 4 answers - 5 points, 3 answers - 4 points, 2 answers - 3 points, 0-1 answers - 2 points.

II . Explaining new material - 15 min

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Teacher: How can a magnetic field be detected? It does not affect our senses - it has no smell, color, taste. True, we cannot say with certainty that there are no creatures in the animal world that feel the magnetic field. In the United States and Canada, electromagnetic barriers have been installed to drive the octopus away from the place of accumulation of fry on the rivers flowing into the Great Lakes. Scientists explain the ability of fish to navigate the expanses of the ocean by their reaction to magnetic fields ...

Today in the lesson we will study how to detect a magnetic field by its effect on an electric current and study the left hand rule.

For any conductor with current placed in a magnetic field and not coinciding with its magnetic lines, this field acts with a certain force, the presence of such a force can be seen using the following experiment: the conductor is suspended on flexible wires, which is connected to batteries through a key. The conductor is placed between the poles of a horseshoe magnet, i.e., is in a magnetic field. When the key is closed, an electric current appears in the circuit, and the conductor starts to move. If you remove the magnet, then when the circuit is closed, the current-carrying conductor will not move. (Demonstration of experience)

Slide 5.

If students can answer: So, from the side of the magnetic field, a certain force acts on the current-carrying conductor, deflecting it from its original position. This force is called the Ampere force.

Let us find out what determines the direction of the Ampère force acting on a current-carrying conductor in a magnetic field. Experience shows that when the direction of the current changes, the direction of movement of the conductor changes, and hence the direction of the force acting on it.

The direction of the force will also change if, without changing the direction of the current, the poles of the magnet are interchanged (i.e., change the direction of the magnetic field lines).
Therefore, the direction of the current in the conductor, the direction of the lines of the magnetic field and the direction of the force acting on the conductor are related.

slide 6.

The direction of the force acting on a current-carrying conductor in a magnetic field can be determined using the left hand rule. In the simplest case, when the conductor is located in a plane perpendicular to the lines of the magnetic field, this rule is as follows: if the left hand is positioned so that the lines of the magnetic field enter the palm perpendicular to it, and four fingers are directed along the current, then set aside on 90 ° the thumb will show the direction of the force acting on the conductor.

Students: for the direction of the current in the external part of the electrical circuit (i.e., outside the current source), the direction from the positive pole of the current source to the negative is taken.

Using the left hand rule, you can determine not only the direction of the force acting in a magnetic field on a current-carrying conductor. According to this rule, we can determine the direction of the current (if we know how the lines of the magnetic field and the force acting on the conductor are directed), the direction of the magnetic lines (if the directions of the current and force are known), the sign.
The force of the magnetic field on a conductor with current is zero if the direction of the current in the conductor coincides with the lines of the magnetic field or is parallel to them.

Slide 7.

Using the Ampere force in technology:

Electric motors;

electrical measuring instruments;

Loudspeakers, speakers.

IV . Fixing the material. Problem solving - 15 min.

slide 8.

slide 9.

slide 10.

Teacher: Ex. 36(1). In which direction will the light aluminum tube roll when the circuit is closed?

Students give answers: according to the rule of the left hand, the lines of the magnetic field enter the palm, electric current flows through the tube, which means that the tube will roll towards the current source.

Results

Today in the lesson we learned how to detect a magnetic field by its effect on an electric current. We studied the Ampere force and its application in technology. Considered the rule of the left hand to determine the direction of Ampère's force.

Slide 11.

V . § 46, ex. 36 (2, 3, 4, 5).

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"Grade 9 _Rule of the left hand_"

Detection of a magnetic field by its effect on an electric current. Left hand rule. Force Ampere.

Insert missing words.

• 1. The magnetic field is generated by ___________.
• 2 . The magnetic field is created by ______________ charged particles.
• 3. For the direction of the magnetic line at any of its points, conventionally take the direction that indicates the _________ pole of the magnetic needle placed at this point.
• 4. The magnetic lines exit the _________ pole of the magnet and enter _______.

• 1. A magnetic field is generated electric shock .
• 2 . The magnetic field is created moving charged particles.
• 3. For the direction of the magnetic line at any point it is conditionally taken the direction that indicates northern the pole of a magnetic needle placed at that point.
• 4. Magnetic lines come out northern poles of the magnet and are included in southern .

• From the side of the magnetic field, a certain force acts on the current-carrying conductor, deflecting it from its original position.
• The direction of the current in the conductor, the direction of the lines of the magnetic field and the direction of the force acting on the conductor are interconnected.
• This force is called Ampere forces(FA).

• left hand rule : if the left hand is positioned so that the lines of the magnetic field enter the palm perpendicular to it, and four fingers are directed along the current, then the thumb set aside by 90 ° will show the direction of the Ampère force acting on the conductor.

• How will the conductor shown in the figure move. The direction of the current is shown by arrows.

• Current-carrying conductors are located between the poles of the magnets. How does each of them move?

• Exercise 36

• Exercise 36 (2,3,4,5) in writing in a notebook

Check Test 1. The magnetic field is generated by electric current. 2. The magnetic field is created by moving charged particles. 3. For the direction of the magnetic line at any of its points, conventionally take the direction that indicates the north pole of the magnetic needle placed at this point. 4. Magnetic lines exit the north pole of the magnet and enter the south.

LEFT HAND RULE for a charged particle If the LEFT HAND is placed so that the lines of the magnetic field enter the palm perpendicular to it, and four fingers are directed along the movement of a positively charged particle (or against the movement of a negatively charged particle), then the thumb set aside by 90 degrees will show the direction of the force acting on the particle.

Is it possible to protect yourself from the action of magnetic forces? Strange as it may seem, the substance that is impenetrable to magnetic forces is the same iron, which is so easily magnetized! Inside the iron ring, the compass needle is not deflected by a magnet placed outside the ring. It is magnetized

"Magnetic field" - 14. The current is directed towards us. 24. 5. Galvanic cell. The positive direction of the normal is taken as the direction of the magnetic field at a given point. Stepanova Ekaterina Nikolaevna Associate Professor of the Department of Physics and Technology, TPU. Electromagnetism. 8. The gimlet rule.

"Magnetic field physics" - Is it possible to see a magnetic field. More precisely, magnetic fields are a necessary consequence of the existence of electric fields. Photographing impossible objects. The electron beam is deflected by the magnetic field. A color change will occur on the TV screen where the magnet is near. You can also consider the magnetic field as a component of the electric field.

“The direction of the magnetic field lines” - Completed by: Kadicheva Anna. Right hand rule. What can be determined using the gimlet rule? It is known that around the electric current there is always a magnetic field. What are called lines of magnetic induction? Electric current and magnetic field are inseparable from each other. For any conductor with current.

"Magnetic field physics lesson" - Equipment. To continue the formation of the basis for understanding the modern scientific picture of the world. Tasks. S. Physics lesson on the topic "magnetic field current." Hans Christian Oersted (1777 - 1851). b). Your conclusion What can change the value of the angle of deflection of the arrow? Change polarity. Repetition assignments.

"Physics Lorentz Force" - The transition from a source at rest to a moving one leads to the appearance of dynamic additions to the static force: In the field Lorentz force: In accordance with the indicated logic Field physics leads to the following expression for the Lorentz force: The force of the electrostatic interaction of two charged objects (Coulomb's law ):

"Lorentz force" - The direction of the Lorentz force. Left hand rule. A magnetic field. Radius of curvature. According to Newton's second law: Hence the radius: In what case does a particle move in a straight line in a magnetic field? Ampère's law? Ampere force: Equation for the current strength in a conductor: Lorentz force Modulus of the Lorentz force. Define the Lorentz force.

In total there are 20 presentations in the topic