electrostatics is the area of Physics that encompasses the study of electrical charges at rest. You phenomenaelectrostatic studied by this area of knowledge arise as a result of the strengthinattraction and repulsion that electrical charges exert on each other. In this text, we will talk about some of the main properties of Electrostatics, such as charge electric, electrification, electric force, electric potential, electric field and potential energy electric.
electric charge
THE electric charge is propertyintrinsic (proper) of the fundamental particles of matter, such as protons and electrons, as well as the pasta. Electrically neutral bodies have the same amount of electrical charges positive and negative. The electric charge unit in the International System of Units it's the Coulomb (Ç).
Furthermore, the electrical charge is a physical quantity quantized, that is, it has a valueMinimum, so that noit's possible find bodies electrified with an electrical charge module less than this value, called fundamental load, usually denoted by the letter and.
Protons and electrons have exactly this electric charge value, about 1,6.10-19 Ç. Therefore, when a body is electrically charged, its charge is a multiplewhole gives chargefundamental, since the electrification takes place from the addition or removal in electrons, since the protons are linked within the coresatomic.
Subtitle:
Q – Electric charge module (C – Coulombs)
no – Number of missing or excess electrons
and – Fundamental load (1.6.10-19 Ç)
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Mind Map: Electrostatics
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Electrification
Electrification is every process capable of generating a difference enter the number of loadspositive and negative of a body. When a body has the same number of positive and negative charges, we say that it is neutral; if these numbers are different, we say he is electrified.
There are basically three electrification processes: a electrification by contact, perfriction and by induction:
THE electrificationpercontact involves two bodies conductors, and at least one of them must be electricallyloaded. When the two bodies come into contact, their electrical charges divide until the two are under the same electrical potential. At the end of the process, the bodies present the same sign of loads.
THE friction electrification involves the supply of energy to two bodies through the friction between them. During the friction (friction), some electrons are ripped from one of the bodies and then captured by the other body. Therefore, it is necessary to verify the affinity of these two bodies in this type of electrification by consulting the triboelectric series.
THE electrificationperinduction occurs by approximationrelative between an electrically charged body, called a inductor, and a conducting body, called the induced. The presence of the inductor generates a separation of charges in the induced body, call of polarization. From this separation, the armature is grounded to the ground, causing its charges to flow through a ground wire.
All electrification processes take place in accordance with the Principlesinconservationgiveschargeelectric and of the energy, i.e, before and after electrification, the number of charges and the amount of energy between charges must be the same.
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electric force
Two electrically charged bodies can exert attraction or repulsion to each other according to their charge signal. Bodies with electrical charges of equal signs repel each other, and bodies whose electrical charges have opposite signsattract each other.
The law that allows us to calculate the modulus of the electrical force exerted between two charges is Coulomb's Law, presented by the following expression:
Subtitle:
F – Electric force (N - Newtons)
k0 – Electrostatic vacuum constant (k0 = 9,0.109 N.m²/C²)
what1,what2 – Electrical charges 1 and 2 (C – Coulombs)
d – Distance between loads 1 and 2 (m)
Electric field
O electric field it's a physical magnitude vector attributed to electrical loads. Every electric charge influences the space around it because of its electric field. We can understand the electric field, therefore, as the influence that electric charges exert on their surroundings. The electric field unit in the International System of Units is the NewtonperCoulomb (N/C) or the Volt per meter (V/m), as both are units equivalents.
See an example:
A given position in space has an electric field of 12.0 N/C generated by an electrical charge. When an electrical charge of 1.0C is placed in this position, it will be acted upon by an electrical force of modulus equal to 12.0 N. If this charge was 2.0C, she would suffer an electrical force of 24.0 N.
The electric field generated by an electric charge Q1 can be calculated using the following expression:
In the expression above, the variable d is the distance from the point where you want to measure the strength of the electric field to the position of the electric charge.
Electric potential
O electric potential it's a physical magnitude climb fully represented by its module and measure in Volts (V) in the System Iinternationalin Uties. This magnitude measures the the amountinenergy provided by an electric field for each Coulomb of cargo.
When a particle is in a region of space subjected to an electrical potential of 100.0V, it will have stored 100.0 J with it (joules) of energy for every 1.0 C of electrical charge it presents. If your cargo is from 2.0C, she will have an energy of 200.0 J, Consequently.
O potentialelectric generated by a module electrical charge Q1 can be calculated using the following expression:
electrical potential energy
When twoor more electrical charges are fixed at a distance d between them they store a form of energy called the electrical potential energy. If one of these charges is released, this energy will be transformed into energykinetics, for example. This energy is measured in joules in the International System of Units.
We can calculate the electrical potential energy between charges using the following expression:
Electrostatics Formulas
Check here the main formulas used in the study of Electrostatics.
→ Electric charge formula
This formula is used to calculate the amount of excess or missing electrical charge in a body. It can also be used to calculate the number of missing or excess electrons.
→ Electric Field Formula
It is used to determine the strength of an electric field produced by a point electric charge what1at a distance d of this load:
→ Electric potential formula
The electrical potential of a point distribution of charges can be calculated using the following formula:
→ Electric force formula (Coulomb's law)
The formula that can be used to calculate the force that an electrical charge what1 exerts on an electrical charge what2,separated by a distance d, is determined by Coulomb's law:
→ Electric potential energy formula
We can calculate the modulus of electrical potential energy between two charges what1 and what2, separated by a distance d, through the following formula:
Summary
Electrostatics is the field of Physics that studies the phenomena produced by electrical charges at rest;
Every electric charge influences the space around it through a vector physical quantity called an electric field;
The electric field is a measure of the electric force exerted on each unit of charge;
The lines perpendicular to the electric field lines define the magnitude of the electric potential produced by the electric charges;
The electrical potential energy between two charges is a scalar quantity that is given in Joules and measures the amount of energy associated with repulsion and mutual attraction between electrical charges;
The modulus of the electrical force between two electrical charges can be determined from Coulomb's law.
Solved Electrostatics Exercise
An electrical charge of 2.0 µC fixed and of negligible size generates, at a distance of 0.5 m, an electric field and electric potential respectively equal to:
Data: k0 = 9.109 N.m²/C².
a) 72.10-3 N/C and 3.6.103 V
b) 12.104 N/C and 36.105 V
c) 72.103 N/C and 54.103 V
d) 72.102 N/C and 3.6.104 V
e) 7.2.103 N/C and 3.6.10-3 V
Feedback: Letter B
Resolution:
Fieldelectric and potentialelectric they are properties inherent in a single electrical charge in space. To calculate the fieldelectric of this load, we use the following equation:
Taking the data provided by the exercise statement, we have to:
To calculate the potentialelectric produced by this load at the same distance (0.5 m), we use the following equation:
Taking the data informed in the statement, we have the following resolution:
By Rafael Hellerbrock
Master in Physics
