When sending uncharged electroscope positive or negative electric charge, you may notice that the leaves of the electroscope will diverge to a smaller or larger angle.
Prikosnёmsya using electrified electroscope sticks to the rod and remember the angle at which the leaves will diverge.In order to give the divergence of the electroscope leaves a larger angle, it is necessary to give him a charge from a larger area of the charged wand.Conversely, the leaves come together, at the touch of a hand to the rod of the electroscope.
Thus, we find that the strength of the electric charge on the bodies is more or less.Therefore, one can speak of such a thing as the value of the charge, and hence of its dimension.
This was possible thanks to the opening at the end of the XVIII century.Law on the interaction of electric charges.This law opened the French physicist Coulomb.
Coulomb's law was discovered empirically: scientist conducted experiments with a torsion balance, which measures the force with which objects interact electrified.
torsion balance consists of a lightweight, non-conductive, no electric charges rocker suspended from the finest metallic thread in a glass vessel of cylindrical shape.At one end of the rod reinforced with a gilded ball of cork, a the other - a counterweight.Its upper end the wire is attached to the center of the head provided with the pointer and the rotary scale having a division, which is used to determine the size of the angle of twist of the wire fastened.
vessel lid has an opening through which the other is supplied on the insulator, the same ball b, which is a ball size.The size of the angular distance between the gold balls a and b are calculated in divisions that are on the cylindrical vessel.To do this, turn the head of the weights at a certain angle, you can change the distance.
After both balls will be charged and installed at any distance, pendant could determine the force with which these balls interact by measuring the angle of twist yarns.
If the device is pre-calibrate, the measured angle of rotation of the head, you can see how hard interact electrified balls.
By changing the distance between the balls pendant found that at constant charges the force with which they interact, will be inversely proportional to twice the distance between their centers.
The issue of measuring the magnitude of the charge on the beads was as follows: if the ball b charge and taking out the device to come into contact with another ball, that exactly half of the charge will go to another ball from the ball b.It thus will be less than twice the charge.By putting the ball back into the appliance b, Coulomb found that at the same distance between the balls, their force of interaction decreases twice - directly proportional to the reduction in value of the charge.
similarly changed the charge of moving the ball a.
These experiences opened the law, which subsequently became known as Coulomb's law, the definition of it as follows: the force of interaction between two point charges is directly proportional to their value is inversely proportional to the square of the distance between the charges and is directed along the line that connects these charges.
Coulomb's law Amonton expressed by the formula:
F = k (q1q2 / r²),
where q1 and q2 - the value of point charges that interact, r - the distance between the charges and k is a constant of proportionality,which depends on the values of the measurement unit will be included in the formula.
This point is called such charges, which are the bodies of any size and shape, which are quite small compared with the distances, which is considered their interaction.
Studies have shown that the magnitude of the force F affects the environment, and the formula which expresses the Coulomb's law applies only in the case where the interaction of charged bodies in a vacuum.
Through Coulomb has installed a unit of electrical discharge.Thus, it is meant a charge current in vacuo to an identical charge, which is at a distance of one centimeter, with a force of one dyne.This is an absolute electrostatic unit of charge.
