Potentialelectric or voltageelectric is the amount of energy needed to move a electric charge unitary between two distinct points of a region with a electric field. O potentialelectric it's a physical magnitude climb measure in volts (V), which is equivalent to joulespercoulomb (J/C) in units SI.
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Electric potential properties
O potentialelectric is the amount of electrical potential energy, in joules, per unit of charge, in coulomb. Understand: asserting that an outlet provides 110V of electrical potential is equivalent to saying that it yields 110 J of energy for each coulomb of electrical charge passing through its terminals.
The electrical potential at the point where the charge what is is directlyproportional to the electrical load module what that produces it, and inversely proportional to the distance d:
As you can see in the figure, all spotsequidistant
(red lines) to the generating load (Q) are in the samepotentialelectric and, therefore, they are called equipotentials. THE formula used to calculate the electrical potential is this:
U – electrical potential (V)
Q – electric charge (C)
k0 – electrostatic vacuum constant (9.0.109 N.m²/C²)
d – distance (m)
The electrical potential can admit signals algebraic, positive and negative,relateddirectly like charge sign that generates the potential and with the distance d up to that charge. This is to say that, in the vicinity of an electrically charged body, there are infinitely many values of electrical potential, determined by the distance to that charge. In this way, an electric potential of a charge will only be exactly equal to 0 when the distance between the point where you want to measure a null potential and the charge is infinitely large.
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There is another way to define electrical potential by relating it to electrical potential energy, here's how:
ANDFootthere – electrical potential energy (J)
Definition of electrical potential
Consider that a chargeelectricpunctualwhat is at a point THE of uniform electric field AND, as shown in the figure, and then is shifted to the point B.
Let's calculate the energy required for the charge to be displacedin betweenyouspotsA and B, separated by a distance d. To do this, we will use the definition of Work:
Remember that the electric force produced by the electric field and acting on the charge q is equal to the product of the charge q with the electric field E:
Joining the previous formulas, we have a different expression for the work performed by electrical force:
Next, we must remember what the relationship between the electric field is like. AND and the electric potential U. Thus:
Finally, we find an expression used to calculate the electrical potential in terms of the work done to shift the electrical charge between points A and B, as we now show:
Since the work done to move the electrical charge between points A and B is equivalent to amount of electrical energy that the load "gained" or "lost", the electrical potential can be understood as a energy to charge ratio, as explained.
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Exercises on electrical potential
Question 1) Between two charged metal plates, spaced 10 cm apart, there is an electric field of 500 V/m. Determine the electrical potential difference between them.
a) 10V
b) 100V
c) 50V
d) 500V
e) 5000 V
Feedback: Letter C
Resolution:
After converting the distance between the plates, transforming it into meters (10 cm = 0.1 m), we will use the formula that relates the electric field to the potential difference, observe:
Through the calculation shown, we found that the potential difference between the plates is 50 V, so the correct alternative is the letter c.
Question 2) Review the statements related to electrical potential:
I – The electric potential is a scalar quantity.
II – The electrical potential measurement unit is the ampere (A).
III – The electric potential at a certain point in space is inversely proportional to the square of the distance to the electric charge.
IV – The electrical potential measurement unit, according to the SI, is the volt (V).
Is(are) true:
a) I and II
b) I and IV
c) II and III
d) I, II and III
e) II, III and IV
Feedback: Letter B
Resolution:
Statements II and III are false, since the unit of measurement is the volt and the electrical potential is inversely proportional to the distance to the load. Thus, statements I and IV are correct.
Question 3) An electrically charged particle, with a charge of 2 mC (2.0.10-3 C), undergoes a work of 5.0 J when transported between two points of an electrical circuit. Determine the potential difference between these points.
a) 3.0.106 V
b) 4,5.102 V
c) 0.5.103 V
d) 2.5.10-3 V
e) 10.10-4 V
Feedback: Letter D
Resolution:
To solve the exercise, just use the formula that relates electrical potential and work, observe:
According to the result obtained, the correct answer is the letter d.
By Rafael Hellerbrock
Physics teacher
Source: Brazil School - https://brasilescola.uol.com.br/fisica/potencial-eletrico-v.htm
