Electrostatic induction- the phenomenon of the guidance of its own electrostatic field, with action on the body of the externalelectric field. The phenomenon is due to redistributionchargesinside conductive bodies, as well as polarization of internal microstructures in non-conductive tel. The external electric field can be significantly distorted near the body with an induced electric field.
There are also some gas clouds associated with the passage passage. Since the terminator is always present in the polar regions, the local medium, due to these effects of particles and gases, can be different. Dust grains and the lunar surface are electrostatically charged with the interaction of the moon with a local plasma medium and photoames of electrons due to solar ultraviolet and X-ray radiation. Dust grains on a scale of 1 μm were observed at an altitude of 100 km above the surface of the moon. These grains can accelerate up through the narrow shell area with a surface electric field.
Dielectrics in the electric field do not behave as the conductor, although they have something in common. Dielectrics differ from the conductors in that they do not have free chargers of charges. Still, they are there, but in very small quantities. In conductors such carriers of charges are electrons freely moving along crystal lattice Metals. But in dielectrics, electrons are firmly connected with their atoms and cannot move freely. When making a dielectric to the electric field, it comes to electrification as well as in the conductor. The difference between dielectrics is that electrons cannot freely move in volume as it happens in the conductors. But under the action of external electric field Inside the dielectric substance molecules, some charge shift appears. Positive shifts along the direction of the field, and negative against. As a result, the surface receives a certain charge. The process of the charge formation on the surface of dielectrics under the action of the electric field is called the polarization of the dielectric. All dielectrics are divided into two categories. Dielectrics belonging to the first category have molecules that even in the absence of an external electric field form dipoles. They are called polar. The polar dielectrics include water ammonia acetone and ether. The dipoles of such dielectrics in the absence of the field are chaotic due to the heat movement. And, consequently, the charge on the surface of such a substance is zero. But when it is introduced into the external electric field, the dipole is there a molecule seek to turn around along the field. It turns out that the positive charge of the previous dipole looks at the negative next. Consequently, they compensate each other. But the dipoles located near the surface itself is not a couple. Thus, uncompensated related charges are formed on the surface of the material. On the one hand positive with the other negative. But this prevents the thermal movement of molecules.
Parasitic forces are associated with such a suspension. Competing interests: The authors stated that there are no competing interests. It is known that electrostatic phenomena enhance both pollination caused by the wind and insects, but have not yet been described for vertebral nectars. Here we demonstrate that the chickenurs of wild Anne can carry positive charges up to 800 pc during the flight. Tribelectric charging, obtained by friction of an insulated hummingbird wing with various plant structures, generated charges up to 700 pcs.
Elektostatic forces can play an important role in pollination indirectly as vectors and animals. Due to gradient electric potential Between the pollen and floral structures, the charged pollen, a wind tolerant, can more effectively cope with the stigma than can charge pollen. The same way electric chargecarrying insects can be sufficient to increase the amount of pollen grains transmitted by their bodies during flower visits. For example, the placement of the charged metal model or the actual attached insect close to the grounded source of pollen grain can cause attraction and, apparently, increase the likelihood of subsequent transfer of pollen insect to another flower.
Figure 1 - polarization of polar dielectric
The second category of dielectrics are those in which there are positive and negative charges inside the molecule. But they are so close to each other that their effect is mutually compensated. But when making such a molecule in the charge field will be shown for some distance. Thus, the dipole is formed. At such molecules do not affect the thermal motion and, therefore, the polarization in them does not depend on temperature.
These electrostatic tools of pollination are currently being studied for agricultural purposes. On the contrary, pollination of bats or birds has not yet been studied relative to the potential role of electrostatics, although 86% of existing family-coated bridges have species pollined by spine, and some specialized nectarists, such as hummingbirds, can potentially attend thousands of colors per day. Currently, there is no data on the magnitude of the electric charge, usually portable by flying vertebral, and it is unknown whether such a charge will be sufficient to enhance pollination.
Figure 2 - Polarization of non-polar dielectric
Charges on the surface of dielectrics, in contrasts of charges induced in conductors, cannot be separated from the surface. When removing the electric field, the polarization will disappear. The charges are redistributed again in the volume of substance. The intensity of the field can not be enlarged infinitely. Since at a certain amount of charges will be shown so much that the structural change in the material will occur, simply speaking, the sample of the dielectric. In this case, it loses its insulating properties.
Here we provide experimental data indicating that the freely flying strollers of Anna can accumulate an electric charge sufficient to attract pollen grains, as well as to displace floral threads and anthers to the beak and the heads of birds. We also demonstrate that frictional contact of the wing with petals and leaves of plants can create high charges that potentially contribute to the transfer of pollen.
Aluminum disc, covered with orange and red electric ribbon, was attached to a copper tube for imitation artificial flower. The feeder is suspended in the square cell of the Faraday with a metal clamp; The cell was grounded and open on one side. The measurement and grounding cables of the charge sensor were connected to the tip of the copper feeder and to the Faraday cell, respectively. The observer clearly saw how each bird visits the feeder, and almost all visits were performed by males.
Concept of electric field
It is known that in the space surrounding electrical charges, the power of the electric field. Numerous experiences over charged bodies fully confirm it. The space surrounding any charged body is an electric field in which electrical forces act.
Since individual hummingbirds were not marked during the experiment, the total number of battles was unknown, and numerous visits of the same person are possible. The relative humidity and temperature of the air inside the cube each time the hummingbird visits were recorded using a combined thermohygrometer. Within one day, the relative humidity was below the minimum measurement point of the sensor, and the humidity on this day was obtained from the neighboring meteorological station Berkeley.
Using this experimental feeder, we measured the charge of wild hummingbirds when they hung under water under various humidity and temperature conditions. The source sensor drift was removed from the sampling route using a linear model, and the net charge was calculated as the difference in the output of the sensor before and after visiting the hummingbird. Combining all data points, we then simulated a charge as a second degree of polynomial function of humidity and temperature, including measurement day as a random factor.
The direction of the forces of the field is called the power lines of the electric field. Therefore, it is conventionally believed that electrical field is a totality silest lines.
Power line fields have certain properties:
The power lines are always out of a positively charged body, and enter the body, charged negatively;
they go out in all directions perpendicular to the surface of the charged body and perpendicular to it;
The attractive forces acting on floral structures charged hummingbirds were studied using stamens recently separated from colors. We are attached by the hummingbirds of the metal model on the support stand with a plastic rod as an insulator, and put it within the above pharade cell. Then we installed a single grounded and disconnected floral chip on the basis of its brass tube and placed next to the pubic model. Both hummingbirds and stamens were turned 90 ° relative to their natural orientation, so the gravitational forces did not contribute to the bending of the thread.
The power lines of the two of the same name charged bodies, as it were, are repelled one of the other, and the variemlessly charged - attract.
The power lines of the electric field are always open, as they burst on the surface of charged, tel. Electrically charged bodies interact with each other: the variemlessly charged are attracted, and the same names are repelled.
Then we handed over the well-known electric charge model using an isolated perina with an attached metallic tip. The other end of Rakhis was attached to the metal cover and grounded metal wire. The hummingbird model was discharged before each test. Then we again turned on the metal tip of the Rahis in the copper bucket to transfer any remaining charge. The copper bucket was connected to the aforementioned charge sensor, which made it possible to measure the net charge on the metal tip of the Rahu.
The total charge of the hummingbird model was designed as the difference between the first and second measurement of the charge from the copper bucket. From recorded video sequences, we digitized the position of the anther during the electric attraction process using special tracking software.
Electrically charged bodies (particles) with charges Q1 and Q2 interact with each other with the force F, which is a vector value and is measured in Newton (H). With variety of body charges, they are attracted to each other, and with the same name - repel.
The force of attraction or repulsion depends on the values \u200b\u200bof charge charges and from the distance between them.
The distance to the model was recorded at the beginning of the rapid movement of the anther due to electrostatic attraction, and its average bend rate was estimated as a distance divided by the next time to contact the model. We also used a charged hummingbird model to determine whether there will be particles with floating dust, similar to the size, for pollen grains, to show electrostatic attraction. Charging the hummingbird model was performed using the Rakhis metal tip and the Van de Grafa generator described above.
Charged bodies are called point if their linear dimensions are small compared to the distance R between the bodies. The magnitude of the force of their interaction F depends on the values \u200b\u200bof charges Q1 and Q2, the distance R between them and the medium in which electrical charges are located.
If there is no air in the space between the bodies, but some other dielectric, i.e., the non-conductor of electricity, then the strength of the interaction between the bodies will decrease.
The electrical charge was measured by induction using a metal bucket connected to the charge sensor; The charged metal tip of the Rakhis was introduced into the bucket and bind to the bucket as before and after we touched the model. It was assumed that the difference between these two charge measurements indicates that the electrical charge is transferred and remains on the model. In the experimental tests, the artificial stitch was first placed close to the forehead of the hummingbird model. Then we carefully touched the artificial stamens with a grounded metal pin, which made the disputes disconnect and fall from the wire.
The value characterizing the properties of the dielectric and showing how many times the strength of the interaction between charges will increase if this dielectric is replaced by air, is called the relative dielectric constant of this dielectric.
Dielectric constant is: for air and gases - 1; For Ebonite - 2 - 4; for mica 5 - 8; for oil 2 - 5; for paper 2 - 2.5; For paraffin - 2 - 2.6.
In one of the experiments, the model was repeatedly charged with values \u200b\u200bcharacteristic of freely flying hummingbirds, and the distance between the particles and the model was measured at which electrostatic attraction became obvious. We also digitized the path of five randomly selected particles attracted to the model when it was charged at 490 pcs, as well as at 840 pcs. As a control, we measured the trajectories for ten particles in the presence of a grounded and, consequently uncharged model. Particle speed and acceleration were calculated as the first and second derivatives of the positioning displacement curves, smoothed by a quinted spline.
Electrostatic induction
If the conductive body and a spherical shape, isolated from the surrounding items, inform the negative electrical charge, i.e., create an excess of electrons in it, then this charge will be evenly distributed over the body surface. This is because the electrons, pushing out one of the other, tend to go to the surface of the body.
We investigated the triboelectric effects that occur when the first grounded of the first grounded, and then an isolated Hummingbird wing, on the tip of the cut-off feather pigeon. The insulated wing was rubbed by hand at 10 Hz against flowering petals or tea plant leaves for about four seconds using a grounded observer. We measured the wing charge before and after friction through the introduction to the aforementioned metal bucket associated with the charge sensor; The difference between these two dimensions was made to indicate that the clean charge is transferred by the friction.
Pose an uncharged body B, also isolated from the surrounding items, in the body of the body A. Then on the surface of the body used electric charges will appear, and a charge opposite to the body A (positive) is formed on the side facing the body A (positive), and on the other side - The charge that is connected with the charge of the body A (negative). Electrical charges, distributing in this way, remain on the surface of the body B until it is in the body field A. If the body b is out of the field or remove the body A, then the electrical charge on the body surface b is neutralized. This method of electrification is called electrostatic induction or electrification by means of influence.
We performed ten repetitions of this measurement sequence for rose and pink leaf petals. Net payments decreased significantly with humidity, but did not change with the air temperature. The distance of attraction has increased significantly with a model charge, but also varied significantly in flower species.
Increased charge model usually increased the rate of attraction, but this effect also depended on the types of flower. The model charge has little influenced the rate of attraction of the pensomemone, the values \u200b\u200bof which were 90% lower than in other species. This component of speed was the same for charged and uncharged cases. Rooting one wing of the hummingbird against the leaves or flower petals, it increased its static charge from the nominally zero grounded state to the average values \u200b\u200bof 620 ± 184 PC and 658 ± 184 PC, respectively.
Obviously, such an electrified state of the body is forced and maintained exclusively by the action of the power of the electric field created by the body A.
If you do the same when the body A will be charged positively, then free electrons with a person's hands will rush to the body b, neutralize it positive chargeAnd the body b will be charged negatively.
Wipes of Wild Anna quench electrostatic charges up to 800 pcs during a forage, which is much higher than positive charges described for forage bees. The pure charge, carrying hummingbirds, usually decreased with an increase in relative humidity, but some charges remained even in conditions close to 100% relative humidity. Other conditions ambient May contribute to accumulation of charge, for example, flight in the rain. Rain drops falling into the atmosphere can reach hundreds of picoculoms, and therefore the transfer of charge when contacting with fog or rain drops is possible for flying hummingbirds that are known to fly effectively even during heavy rain.
The higher the degree of electrification of the body A, that is, the higher its potential, the higher the potential can be electrified by means of electrostatic induction body B.
Thus, we concluded that the phenomenon of electrostatic induction makes it possible under certain conditions to accumulate on the surface of conductive bodies.
Since the animal pollination of colors is mainly carried out by volunteer taxa, these data, together with documented electrical charges on woven beekeepers, assume that the electrostatic transfer of pollen into animal vectors can be more common than is currently recognized. At low distances, electrostatic forces can easily exceed the magnitude of other forces affecting pollen grains. Assuming that bee container is 1-2 PF, this voltage corresponds to electrostatic charging Less than 100 PCs.
Each body can be charged to a certain limit, i.e. to a certain potential; Increased potential over the utmost entails body discharge into the surrounding atmosphere. For different bodies, a different amount of electricity needs to bring them to the same potential. In other words, different bodies contain different amounts of electricity, i.e. possess different electrical capacity (or just with a capacity).
The electrical capacity is called the body's ability to accommodate a certain amount of electricity, increasing its potential to a certain amount. The larger the surface of the body, the greater the electric charge can accommodate this body.
If the body has a ball shape, then it is directly dependent on the radius of the ball. The container is measured by the Faradays.
Faraday - the capacity of this body, which, having received the charge of electricity in one pendant, increases its potential for one volt. 1 Faraday \u003d 1,000,000 microfrades.
Electrical capacity, i.e., the property of conductive bodies accumulate an electric charge, is widely used in electrical engineering. The device is based on this property.
Capacity condenser
The condenser consists of two metal plates (plates), isolated one from another air layer or any other dielectric (mica, paper, etc.).
If one of the plates report a positive charge, and the other is negative, that is, the opposite to charge them, then the charges of the plates, mutually attracting, will be kept on the plates. This allows you to focus on the plates a much larger amount of electricity than if you charge them in a distance from one another.
Therefore, it can serve as a device with a significant amount of electricity on its plates. In other words, the condenser is electrical energy drive.
Capacitance of the capacitor is:
C \u003d E. S / 4. π L.
where C is a container; e - the dielectric constant dielectric; S is the area of \u200b\u200bone plate in cm2, π-proposed number, equal to 3.14; L - distance between plates in cm.
From this formula, it can be seen that with increasing area plates, the capacitor capacity increases, and with an increase in the distance between them decreases.
Let us explain this dependence. The greater the area of \u200b\u200bthe plates, the more electricity they can accommodate, and consequently, the capacitance of the capacitor will be greater.
With a decrease in the distance between the plates, the mutual influence (induction) increases between their charges, which allows you to focus on the plates a larger amount of electricity, and therefore, increase the capacitor capacitance.
Thus, if we want to get a large capacitance capacitor, we must take the plates of a large area and isolate them with each other with a thin layer of dielectric.
The formula also shows that with an increase in the dielectric permeability of the dielectric capacitance of the capacitor increases.
Consequently, condensers equal to their geometric sizes, but containing various dielectrics, have a different container.
If, for example, take a capacitor with an air dielectric, the dielectric constant of which is equal to one, and put between its plates with a dielectric constant 5, then the capacitance capacitance will increase by 5 times.
That is why for obtaining large containers as dielectrics, materials such as mica, paper impregnated with paraffin, and others, the dielectric permeability of which is significantly larger than that of air.
In accordance with this, the following types of condensers are distinguished: air, with a solid dielectric and with a liquid dielectric.
Capacitor charge and discharge. Shift current
Include a constant capacitor capacitor into a chain. When installing the switch to contact, the condenser will be included in the battery circuit. The Milliammeter arrow at the time of turning on the capacitor to the chain will be rejected and then turns to zero.
Consequently, the chain passed electricity in a certain direction. If the switch is now to contact B (i.e. to close the plates), the Milliammmeter arrow will be dismissed to the other side and again will be zero. Consequently, the circuit also passed the current, but another direction. We will analyze this phenomenon.
When the capacitor was connected to the battery, it was charged, that is, his plates received one positive, and the other negative charges. The charge continued until the capacitor was equal to the battery voltage. The milliammeter included in the chain sequentially showed the charge current of the capacitor, which stopped as soon as the capacitor was charged.
When the capacitor was disconnected from the battery, it remained charged, and the potential difference between its plates was equal to the battery voltage.
However, as soon as the condenser was closed, it began to be discharged, and the discharge current went along the chain, but already in the direction, the reverse order of charge. It lasted until the potential difference between the plates had disappeared, that is, until the capacitor was discharged.
Consequently, if the condenser is included in the chain direct currentThe chain will go to the chain only at the time of the charge of the capacitor, and in the future there will be no current in the chain, since the chain will be torn to the dielectric condenser.
Therefore, they say that "The capacitor does not miss DC."
The amount of electricity (q), which can be focused on the condenser plates, its capacity (C) and the value of the voltage condenser (U) is associated with the following dependence: Q \u003d Cu.
This formula shows that the greater the capacitance of the capacitor, the greater the amount of electricity can be focused on it, without increasing the voltage on its plates.
Increasing the voltage at unchanged capacity also leads to an increase in the amount of electricity supplemented by a capacitor. However, if there is a lot of voltage to cover the capacitor, the condenser may be "pierced", i.e., under the action of this voltage, the dielectric in some place will be collapsed and passed through itself. The condenser will stop its action. To avoid damage to capacitors, they indicate the validity of the permissible operating voltage.
Polarization phenomenon dielectric
We will analyze now what happens in a dielectric during charge and discharge of the capacitor and why depends the magnitude of the container from the dielectric permeability of the dielectric?
The answer to this question gives us the electronic theory of the structure of the substance.
In a dielectric, as in any insulator, there are no free electrons. In the dielectric atoms, the electrons are firmly connected to the nucleus, so the voltage applied to the condenser plates does not cause a dielectric of the directional electron movement, that is, the electric current, as it happens in the conductors.
However, under the action of the electric field forces created by charged plates, electrons rotating around the atomic core are shifted towards a positively charged condenser plate. At the same time, at the same time, it would be pulled in the direction of the power lines of the field. This condition of the dielectric atoms is called polarized, and the phenomenon itself is the polarization of the dielectric.
When the condenser's discharge, the polarized state of the dielectric is broken, i.e., the displacement of electrons relative to the kernel disappeared by polarization, and atoms come to their usual unpolarized state. It has been established that the presence of the dielectric relaxes the field between the condenser plates.
Different dielectrics under the action of the same electrical field are polarized to varying degrees. The easier the dielectric polarizes, the more relaxes the field. Polarization of air, for example, leads to a smaller weakening of the field than the polarization of any other dielectric.
But the weakening of the field between the plates of the capacitor allows you to focus on them more electricity q for the same voltage U, which in turn leads to an increase in the capacitance of the capacitor, since C \u003d Q / U.
So, we came to the conclusion - the greater the dielectric permeability of the dielectric, the greater the capacitor, which contains this dielectric in its composition.
The displacement of electrons in the dielectric atoms, which happened, as we have already spoken, under the action of the electric field forces, forms in the dielectric, at the first moment of the field, the electric current, called the shift current. So it is named because, in contrast to current conductivity in metal conductors, the bias current is formed only by the displacement of electrons moving within its atoms.
The presence of this offset current leads to the fact that the condenser connected to the source alternating current, becomes its conductor.
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