What allows us to say that there is an electric field around a charged body? Electric field - Knowledge Hypermarket. Biological effect of the electromagnetic field

As is known, characteristic feature conductors is that they always have large number mobile charge carriers, i.e. free electrons or ions.

Inside a conductor, these charge carriers, generally speaking, move chaotically. However, if there is an electric field in the conductor, then the chaotic movement of the carriers is superimposed by their ordered movement in the direction of action electrical forces. This directed movement of mobile charge carriers in a conductor under the influence of a field always occurs in such a way that the field inside the conductor is weakened. Since the number of mobile charge carriers in the conductor is large (the metal contains about free electrons), their movement under the influence of the field occurs until the field inside the conductor disappears completely. Let's find out in more detail how this happens.

Let a metal conductor, consisting of two parts tightly pressed to each other, be placed in an external electric field E (Fig. 15.13). On free electrons In this conductor, field forces act to the left, i.e., opposite to the field strength vector. (Explain why.) As a result of the displacement of electrons under the influence of these forces, an excess of positive charges appears at the right end of the conductor, and an excess of electrons at the left end. Therefore, an internal field (field of displaced charges) arises between the ends of the conductor, which in Fig. 15.13 is shown with dotted lines. Inside

conductor, this field is directed towards the external one and each free electron remaining inside the conductor acts with a force directed to the right.

Strength first more power and their resultant is directed to the left. Therefore, the electrons inside the conductor continue to shift to the left, and the internal field gradually increases. When quite a lot of free electrons accumulate at the left end of the conductor (they still make up an insignificant share from them total number), the force will be equal to the force and their resultant will be equal to zero. After this, the free electrons remaining inside the conductor will move only chaotically. This means that the field strength inside the conductor is zero, i.e., that the field inside the conductor has disappeared.

So, when a conductor enters an electric field, it becomes electrified so that at one end it appears positive charge, and on the other there is a negative charge of the same magnitude. This electrification is called electrostatic induction or electrification by influence. Note that in this case only the conductor’s own charges are redistributed. Therefore, if such a conductor is removed from the field, its positive and negative charges will again be evenly distributed throughout the entire volume of the conductor and all its parts will become electrically neutral.

It is easy to verify that at the opposite ends of a conductor electrified by influence, there are indeed equal amounts of charges of opposite sign. Let's divide this conductor into two parts (Fig. 15.13) and then remove them from the field. By connecting each part of the conductor to a separate electroscope, we will make sure that they are charged. (Think about how you can show that these charges have opposite signs.) If we reconnect the two parts so that they form one conductor, we will find that the charges are neutralized. This means that before the connection, the charges on both parts of the conductor were equal in magnitude and opposite in sign.

The time during which the conductor is electrified by the influence is so short that the balance of charges on the conductor occurs almost instantly. In this case, the tension, and therefore the potential difference inside the conductor, becomes everywhere equal to zero. Then for any two points inside the conductor the relation is true

Consequently, when the charges on the conductor are in equilibrium, the potential of all its points is the same. This also applies to a conductor electrified by contact with a charged body. Let's take a conducting ball and place a charge at point M on its surface (Fig. 15.14). Then in the explorer on short time a field arises, and at point M an excess charge occurs. Under the influence of the forces of this field

the charge is evenly distributed over the entire surface of the ball, which leads to the disappearance of the field inside the conductor.

So, regardless of how the conductor is electrified, when the charges are in equilibrium, there is no field inside the conductor, and the potential of all points of the conductor is the same (both inside and on the surface of the conductor). At the same time, the field outside the electrified conductor, of course, exists, and its intensity lines are normal (perpendicular) to the surface of the conductor. This can be seen from the following reasoning. If the tension line were somewhere inclined to the surface of the conductor (Fig. 15.15), then the force acting on the charge at this point on the surface could be decomposed into components. Then, under the influence of a force directed along the surface, the charges would move along the surface of the conductor, which There should be no charge equilibrium. Consequently, when the charges on the conductor are in equilibrium, its surface is an equipotential surface.

If there is no field inside a charged conductor, then bulk density charges in it (the amount of electricity per unit volume) must be zero everywhere.

Indeed, if there was a charge in any small volume of a conductor, then an electric field would exist around this volume.

In field theory it has been proven that at equilibrium, all the excess charge of an electrified conductor is located on its surface. This means that all inner part This conductor can be removed and nothing will change in the arrangement of charges on its surface. For example, if two solitary metal balls of equal size, one of which is solid and the other is hollow, are equally electrified, then the fields around the balls will be the same. This was first proven experimentally by M. Faraday.

So, if a hollow conductor is placed in an electric field or electrified by contact with a charged body, then

When the charges are in equilibrium, the field inside the cavity will not exist. Electrostatic protection is based on this. If any device is placed in a metal case, then external electric fields will not penetrate inside the case, i.e., the operation and readings of such a device will not depend on the presence and changes of external electric fields.

Let us now find out how the charges are arranged along outer surface conductor. Let's take a metal mesh on two insulating handles, to which paper leaves are glued (Fig. 15.16). If you charge the mesh and then stretch it (Fig. 15.16, a), the leaves on both sides of the mesh will separate. If you bend the mesh into a ring, then only the leaves with outside grids (Fig. 15.16, b). By giving the mesh a different bend, you can make sure that the charges are located only on the convex side of the surface, and in those places where the surface is more curved ( smaller radius curvature), more charges accumulate.

So, the charge is distributed evenly only over the surface of a spherical conductor. At free form conductor surface density charges a, and therefore the field strength near the surface of the conductor is greater where the curvature of the surface is greater. The charge density is especially high on the protrusions and on the tips of the conductor (Fig. 15.17). This can be verified by touching various points of the electrified conductor with a probe and then touching the electroscope. An electrified conductor that has points or is equipped with a point quickly loses its charge. Therefore, the conductor on which the charge must be stored for a long time, should not have any points.

(Think about why the rod of an electroscope ends in a ball.)

Let's hang a charged cartridge case on a thread and bring an electrified glass rod to it. Even in the absence of direct contact, the sleeve on the thread deviates from the vertical position, being attracted to the stick (Fig. 13).

Charged bodies, as we see, are able to interact with each other at a distance. How is the action transmitted from one of these bodies to another? Maybe it's all about the air between them? Let's find out this by experience.

Let's place a charged electroscope (with the glasses removed) under the bell of the air pump, and then pump out the air from under it. We will see that in airless space the leaves of the electroscope will continue to repel each other (Fig. 14). This means that air does not participate in the transmission of electrical interaction. Then by what means does the interaction of charged bodies take place? The answer to this question was given in their works by the English scientists M. Faraday (1791-1867) and J. Maxwell (1831-1879).

According to the teachings of Faraday and Maxwell, the space surrounding a charged body differs from the space around unelectrified bodies. There is an electric field around charged bodies. This field is used to electrical interaction.

Electric field represents special kind matter, distinct from matter and existing around any charged bodies.

It is impossible to see it or touch it. About existence electric field can only be judged by his actions.

Simple experiments allow us to establish basic properties of the electric field.

1. The electric field of a charged body acts with some force on any other charged body that finds itself in this field.

This is evidenced by all experiments on the interaction of charged bodies. So, for example, a charged sleeve that found itself in the electric field of an electrified stick (see Fig. 13) was subjected to the force of attraction towards it.

2. Near charged bodies the field they create is stronger, and farther away it is weaker.

To verify this, let us again turn to the experiment with a charged cartridge case (see Fig. 13). Let's start bringing the stand with the cartridge case closer to the loaded stick. We will see that as the sleeve approaches the stick, the angle of deviation of the thread from the vertical will become larger and larger (Fig. 15). An increase in this angle indicates that the closer the sleeve is to the source of the electric field (an electrified rod), the greater the force that this field acts on it. This means that near a charged body the field it creates is stronger than at a distance.

It should be borne in mind that not only a charged stick acts on a charged sleeve with its electric field, but also the sleeve, in turn, acts on the stick with its electric field. It is in this mutual action on each other that the electrical interaction of charged bodies is manifested.

The electric field also manifests itself in experiments with dielectrics. When a dielectric is exposed to an electric field, the positively charged parts of its molecules ( atomic nuclei) under the influence of the field are shifted in one direction, and the negatively charged parts (electrons) are shifted in the other direction. This phenomenon is called dielectric polarization. It is polarization that explains the simplest experiments on the attraction of light pieces of paper by an electrified body. These pieces are generally neutral. However, in the electric field of an electrified body (for example, a glass rod), they become polarized. On the surface of the piece that is closer to the stick, a charge appears that is opposite in sign to the charge of the stick. Interaction with it leads to the attraction of pieces of paper to the electrified body.

The force with which an electric field acts on a charged body (or particle) is called electrical force:

F el - electric force.

Under the influence of this force, a particle caught in an electric field acquires acceleration a, which can be determined using Newton’s second law:

a = F el / m (6.1)

where m is the mass of a given particle.

Since Faraday's time graphic image electric field, it is customary to use force lines.

These are lines indicating the direction of the force acting in this field on a positively charged particle placed in it. The field lines created by a positively charged body are shown in Figure 16, a. Figure 16, b shows the field lines created by a negatively charged body.

A similar picture can be observed using a simple device called an electric plume. By giving him a charge, we will see how all his paper strips disperse into different sides and will be located along power lines electric field (Fig. 17).

When a charged particle enters an electric field, its speed in this field can either increase or decrease. If the charge of a particle q>0, then when moving along the lines of force it will accelerate, and when moving in opposite direction brake. If the particle charge q< 0, то все будет наоборот ее скорость будет уменьшаться при движении в направлении силовых линий и увеличиваться при движении в противоположном направлении.

1. What is an electric field? 2. How does a field differ from matter? 3. List the main properties of the electric field. 4. What do electric field lines indicate? 5. How is the acceleration of a charged particle moving in an electric field found? 6. In what case does an electric field increase the speed of a particle and in what case does it decrease it? 7. Why are neutral pieces of paper attracted to an electrified body? 8. Explain why, after charging the electric sultan, its paper strips diverge in different directions.

Experimental task. Electricize the comb on your hair, then touch it to a small piece of cotton wool (fluff). What will happen to the cotton wool? Shake the fluff from the comb and, when it is in the air, make it float at the same height by placing an electrified comb from below at some distance. Why does the fluff stop falling? What will keep her in the air?

The electric field is one of the theoretical concepts, explaining the phenomena of interaction between charged bodies. The substance cannot be touched, but its existence can be proven, which was done in hundreds of natural experiments.

Interaction of charged bodies

We are accustomed to considering outdated theories a utopia, yet men of science are not at all stupid. Today Franklin’s doctrine of electric fluid sounds funny; the prominent physicist Apinus dedicated an entire treatise. Coulomb's law was discovered experimentally based on torsion scales, similar methods were used by Georg Ohm when deducing the known. But what lies behind all this?

We must admit that the electric field is simply another theory, not inferior to the Franklin fluid. Today two facts are known about the substance:

The stated facts laid the basis for the modern understanding of interactions in nature and act as a support for the theory of short-range interaction. In addition to this, scientists have put forward other assumptions about the essence of the observed phenomenon. The theory of short-range action implies the instantaneous distribution of forces without the participation of the ether. Since phenomena are more difficult to sense than an electric field, many philosophers have dubbed such views idealistic. In our country they were successfully criticized Soviet power, since, as you know, the Bolsheviks did not like God, they pecked at every opportunity the idea of the existence of something “depending on our ideas and actions” (while studying Juna’s superpowers).

Franklin explained the positive and negative charges of bodies by excess and insufficiency of electrical fluid.

Electric field characteristics

The electric field is described by a vector quantity - intensity. An arrow whose direction coincides with the force acting at a point on a unit positive charge, the length of which is proportional to the magnitude of the force. Physicists find it convenient to use potential. The quantity is scalar; it is easier to imagine it using the example of temperature: at each point in space there is a certain value. Electric potential refers to the work done to move a unit charge from a point of zero potential to a given point.

A field described in the above manner is called irrotational. Sometimes called potential. The electric field potential function is continuous and varies smoothly over the extent of space. As a result, we select points of equal potential that fold the surfaces. For a unit charge sphere: further object, weaker field(Coulomb's law). Surfaces are called equipotential.

To understand Maxwell's equations, understand several characteristics vector field:

Gradient electric potential called a vector, the direction coincides with the fastest growth of the field parameter. The faster the value changes, the greater the value. The gradient is directed from smaller value potential for more:

The gradient is perpendicular to the equipotential surface.
The greater the gradient, the closer the location of equipotential surfaces that differ from each other by specified value electric field potential.
The potential gradient, taken with the opposite sign, is the electric field strength.

Electric potential. Gradient "climbing uphill"

Divergence is scalar quantity, calculated for the electric field strength vector. It is analogous to a gradient (for vectors), shows the rate of change of a value. The need to introduce an additional characteristic: the vector field has no gradient. Therefore, the description requires a certain analogue - divergence. Parameter in mathematical notation similar to a gradient, denoted Greek letter nabla, used for vector quantities.
The rotor of the vector field is called a vortex. Physically, the value is zero when the parameter changes uniformly. If the rotor is non-zero, closed line bends occur. Potential fields point charges by definition, there is no vortex. The lines of tension in this case are not necessarily straight. They simply change smoothly, without forming vortices. A field with a non-zero rotor is often called solenoidal. The synonym is often used - vortex.
The total flux of the vector is represented by the surface integral of the product of the electric field strength and the elementary area. The limit of magnitude when the body's capacitance tends to zero represents the divergence of the field. The concept of limit is studied in senior classes high school, the student can get some idea about the subject of discussion.

Maxwell's equations describe a time-varying electric field and show that in such cases a wave arises. It is generally accepted that one of the formulas indicates the absence of isolated magnetic charges(poles). Sometimes in the literature we come across a special operator – the Laplacian. Denoted as the square of the nabla, calculated for vector quantities, represented by the divergence of the field gradient.

Using these quantities, mathematicians and physicists calculate electric and magnetic fields. For example, it has been proven: only an irrotational field (point charges) can have a scalar potential. Other axioms have been invented. The vortex field of the rotor is devoid of divergence.

We can easily use such axioms as the basis for describing the processes occurring in real existing devices. Anti-gravity, perpetual motion machine would be a good help to the economy. If no one has succeeded in putting Einstein’s theory into practice, Nikola Tesla’s achievements are being studied by enthusiasts. There is no rotor or divergence.

A Brief History of the Development of the Electric Field

The formulation of the theory was followed by numerous works on the application of electric and electromagnetic fields in practice, the most famous of which in Russia is considered to be Popov’s experience in transmitting information through the air. A number of questions arose. Maxwell's harmonious theory is powerless to explain the phenomena observed during the passage electromagnetic waves through ionized media. Planck hypothesized that radiant energy is emitted in measured portions, later called quanta. Diffraction of individual electrons, kindly demonstrated on YouTube in English, was discovered in 1949 Soviet physicists. The particle simultaneously exhibited wave properties.

This tells us: modern performance about the electric field constant and variable are far from perfect. Many people know Einstein, but are powerless to explain what the physicist discovered. The 1915 theory of relativity links electrical, magnetic field and gravity. True, no formulas were presented in the form of a law. Today it is known: there are particles that move faster than the propagation of light. Another stone in the garden.

Unit systems were constantly changing. The initially introduced GHS, based on the work of Gauss, is not convenient. The first letters indicate the basic units: centimeter, gram, second. Electromagnetic quantities added to the GHS in 1874 by Maxwell and Thomson. The USSR began using the ISS (meter, kilogram, second) in 1948. The introduction of the SI system (GOST 9867) in the 60s of the 20th century put an end to the battles, where the electric field strength is measured in V/m.

Using an electric field

Accumulation occurs in capacitors electric charge. Consequently, a field is formed between the plates. Since the capacitance directly depends on the magnitude of the voltage vector, in order to increase the parameter, the space is filled with a dielectric.

Indirectly, electric fields are used by picture tubes and Chizhevsky chandeliers; the grid potential controls the movement of electron tube beams. Despite the lack of a coherent theory, electric field effects underlie many images.

What is an electric field?

Let's place a charged electroscope (with the glasses removed) under the bell of the air pump, and then pump out the air from under it. We will see that in airless space the leaves of the electroscope will still repel each other (Fig. 14). This means that air does not participate in the transmission of electrical interaction. Then by what means does the interaction of charged bodies take place? The answer to this question was given in their works by the English scientists M. Faraday (1791-1867) and J. Maxwell (1831-1879).

Electrical field is a special type of matter, different from matter and existing around any charged bodies.

It is impossible to see it or touch it. The existence of an electric field can be judged only by its actions.

Basic properties of the electric field

Simple experiments allow us to establish basic properties of the electric field.

1. The electric field of a charged body acts with some force on any other charged body that finds itself in this field.

2. Near charged bodies, the field they create is stronger, and farther away it is weaker.

It should be borne in mind that not only a charged stick acts on a charged sleeve with its electric field, but also the sleeve, in turn, acts on the stick with its electric field. It is in such mutual action on each other that the electrical interaction charged bodies.

The electric field also manifests itself in experiments with dielectrics. When a dielectric is in an electric field, the positively charged parts of its molecules (atomic nuclei) are shifted in one direction under the influence of the field, and the negatively charged parts (electrons) are shifted in the other direction. This phenomenon is called dielectric polarization. It is polarization that explains the simplest experiments on the attraction of light pieces of paper by an electrified body. These pieces are generally neutral. However, in the electric field of an electrified body (for example, a glass rod), they become polarized. On the surface of the piece that is closer to the stick, a charge appears that is opposite in sign to the charge of the stick. Interaction with it leads to the attraction of pieces of paper to the electrified body.

Electric power

The force with which an electric field acts on a charged body (or particle) is called electrical force:

Fel- electric force.

Under the influence of this force, a particle caught in an electric field acquires acceleration A, which can be determined using Newton's second law:

Where m is the mass of a given particle.

Since the time of Faraday, it has been customary to use power lines.

Electric field lines- these are lines indicating the direction of the force acting in this field on a positively charged particle placed in it. The field lines created by a positively charged body are shown in Figure 16, a. Figure 16, b shows the field lines created by a negatively charged body.

A similar picture can be observed using a simple device called electric plume. Having given it a charge, we will see how all its paper strips will disperse in different directions and will be located along the electric field lines (Fig. 17).

When a charged particle enters an electric field, its speed in this field can either increase or decrease. If the charge of a particle q>0, then when moving along the lines of force it will accelerate, and when moving in the opposite direction it will slow down. If the particle charge q<0, то все будет наоборот ее скорость будет уменьшаться при движении в направлении силовых линий и увеличиваться при движении в противоположном направлении.

It's interesting to know

From today's topic about the electric field, we learned that it exists in the space that is located around the electric charge.

Let's see how, using directional lines of force, we can depict this electric field using graphs:

You might be interested to know that electric fields of varying strengths operate in our atmosphere. If we consider the electric field from the point of view of the universe, then usually the Earth has a negative charge, but the bottom of the clouds is positive. And charged particles such as ions are contained in the air and its content varies depending on various factors. These factors depend both on the time of year and on weather conditions and the frequency of the atmosphere.

And since the atmosphere is permeated with these particles, which, being in continuous movement and characterized by changes either into positive or negative ions, tend to affect human well-being and health. And the most interesting thing is that a large predominance of positive ions in the atmosphere can cause unpleasant sensations in our body.

Biological effect of the electromagnetic field

Now let’s talk to you about the biological effect of EMF on human health and its impact on living organisms. It turns out that living organisms that are in the zone of influence of the electromagnetic field are subject to strong factors of its influence.

Long-term exposure to an electromagnetic field has a negative impact on a person’s health and well-being. For example, in a person with allergic diseases, such exposure to EMF can cause an attack of epilepsy. And if a person stays in an electromagnetic field for a longer period of time, diseases not only of the cardiovascular and nervous systems can develop, but also cause cancer.

Scientists have proven that where there is a strong electric field, behavioral changes can be observed in insects. This negative impact can manifest itself in the form of aggression, anxiety and decreased performance.

Under such influence, abnormal development can also be observed among plants. Under the influence of an electromagnetic field, plants can change in size, shape and number of petals.

Interesting Facts Related to Electricity

Discoveries in the field of electricity are one of the most important achievements of man, because modern life without this discovery is now even difficult to imagine.

Did you know that in some areas of Africa and South America there are villages where electricity is still not available? And do you know how people get out of this situation? It turns out that they illuminate their homes with the help of insects such as fireflies. They fill glass jars with these insects and use fireflies to get light.

Do you know about the ability of bees to accumulate a positive charge of electricity during flight? But flowers have a negative electrical charge, and thanks to this, their pollen itself is attracted to the bee’s body. But the most interesting thing is that the field of such contact between a bee and a flower, the plant’s electric field changes and, as it were, gives a signal to other bees about the absence of pollen on this plant.

But in the world of fish, the most famous electric hunters are stingrays. To neutralize its prey, the stingray uses electrical discharges to paralyze it.

Did you know that electric eels have the strongest electrical discharge? These freshwater fish have a current discharge voltage that can reach 800 V.

Homework

1. What is an electric field?
2. How does a field differ from matter?
3. List the main properties of the electric field.
4. What do electric field lines indicate?
5. How is the acceleration of a charged particle moving in an electric field found?
6. In what case does an electric field increase the speed of a particle and in what case does it decrease it?
7. Why are neutral pieces of paper attracted to an electrified body?
8. Explain why, after charging the electric sultan, its paper strips diverge in different directions.

Experimental task.

Electricize the comb on your hair, then touch it to a small piece of cotton wool (fluff). What will happen to the cotton wool? Shake the fluff from the comb and, when it is in the air, make it float at the same height by placing an electrified comb from below at some distance. Why does the fluff stop falling? What will keep her in the air?

S.V. Gromov, I.A. Rodina, Physics 9th grade

What allows us to say that there is an electric field around a charged body?

The presence of electromagnetic voltage and vortex fields.
the effect of an electric field on a charge.
simple experience:
1. take a wooden stick and tie a sleeve made from a shiny chocolate wrapper to it with a silk thread.
2. rubbing the handle on hair or wool
3. bring the handle to the sleeve - the sleeve will deviate
this allows us to assert that there is an electric field around a charged body (in this case, a pen)))
someone help me solve this problem
http://otvet.mail.ru/question/94520561
everything is in the textbook)
Link (electrono.ru Electric field strength, electric...)
- In the space around an electrically charged body there is an electric field, which is one of the types of matter. An electric field has a supply of electrical energy, which manifests itself in the form of electrical forces acting on charged bodies in the field.
The electric field is conventionally depicted in the form of electric lines of force, which show the directions of action of the electric forces created by the electric field.
Electric lines of force diverge in different directions from positively charged bodies and converge at bodies with a negative charge. The field created by two flat oppositely charged parallel plates is called uniform.
The electric field can be made visible by placing gypsum particles suspended in liquid oil into it: they rotate along the field, positioning themselves along its lines of force. A uniform field is an electric field in which the intensity is the same in magnitude and direction at all points in space.
Wikipedia: To quantitatively determine the electric field, a force characteristic is introduced - electric field strength - a vector physical quantity equal to the ratio of the force with which the field acts on a positive test charge placed at a given point in space to the magnitude of this charge. The direction of the tension vector coincides at each point in space with the direction of the force acting on the positive test charge.
The field between two oppositely charged flat metal plates is approximately uniform. In a uniform electric field, the tension lines are directed parallel to each other.
Recharge yourself and pour some fluff out of your pillow. Everything will be very clear.
If you bring another electrically charged object to the first one, it will also be electric. charged object, then you can see their interaction, which proves the existence of an electric field.
Allows you to calculate the laws of physics
An electric field is a special form of matter that exists around bodies or particles with an electric charge, as well as in free form in electromagnetic waves. The electric field is directly invisible, but can be observed by its action and with the help of instruments. The main effect of the electric field is the acceleration of bodies or particles with an electric charge.
The electric field can be considered as a mathematical model that describes the value of the electric field strength at a given point in space. Douglas Giancoli wrote: “It should be emphasized that the field is not some kind of substance; or rather, it is an extremely useful concept... The question of “reality” and the existence of the electric field is actually a philosophical, rather even metaphysical question. In physics, the concept of field has proven extremely useful - it is one of the greatest achievements of the human mind."

The electric field is one of the components of a single electromagnetic field and a manifestation of electromagnetic interaction.

Physical properties of the electric field
At present, science has not yet achieved an understanding of the physical essence of fields such as electric, magnetic and gravitational, as well as their interaction with each other. So far, the results of their mechanical effects on charged bodies have only been described, and there is also a theory of electromagnetic waves described by Maxwell’s Equations.

Field effect - The field effect is that when an electric field is applied to the surface of an electrically conducting medium, the concentration of free charge carriers in its near-surface layer changes. This effect underlies the operation of field-effect transistors.

The main effect of the electric field is the force effect on stationary (relative to the observer) electrically charged bodies or particles. If a charged body is fixed in space, then it does not accelerate under the influence of force. The magnetic field (the second component of the Lorentz force) also exerts a force on moving charges.

Observing the electric field in everyday life
In order to create an electric field, it is necessary to create an electric charge. Rub some dielectric on wool or something similar, such as a plastic pen on your own hair. A charge will be created on the handle, and an electric field will be created around it. A charged pen will attract small pieces of paper. If you rub a larger object, such as a rubber band, on wool, then in the dark you will be able to see small sparks resulting from electrical discharges.

An electric field often occurs near the television screen when the television receiver is turned on or off. This field can be felt by its effect on the hairs on the hands or face.

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