What is Electrical potential: Definition and 113 Discussions

The electric potential (also called the electric field potential, potential drop, the electrostatic potential) is the amount of work energy needed to move a unit of electric charge from a reference point to the specific point in an electric field with negligible acceleration of the test charge to avoid producing kinetic energy or radiation by test charge. Typically, the reference point is the Earth or a point at infinity, although any point can be used. More precisely it is the energy per unit charge for a small test charge that does not disturb significantly the field and the charge distribution producing the field under consideration.
In classical electrostatics, the electrostatic field is a vector quantity which is expressed as the gradient of the electrostatic potential, which is a scalar quantity denoted by V or occasionally φ, equal to the electric potential energy of any charged particle at any location (measured in joules) divided by the charge of that particle (measured in coulombs). By dividing out the charge on the particle a quotient is obtained that is a property of the electric field itself. In short, electric potential is the electric potential energy per unit charge.
This value can be calculated in either a static (time-invariant) or a dynamic (varying with time) electric field at a specific time in units of joules per coulomb (J⋅C−1), or volts (V). The electric potential at infinity is assumed to be zero.
In electrodynamics, when time-varying fields are present, the electric field cannot be expressed only in terms of a scalar potential. Instead, the electric field can be expressed in terms of both the scalar electric potential and the magnetic vector potential. The electric potential and the magnetic vector potential together form a four vector, so that the two kinds of potential are mixed under Lorentz transformations.
Practically, electric potential is always a continuous function in space; Otherwise, the spatial derivative of it will yield a field with infinite magnitude, which is practically impossible. Even an idealized point charge has 1 ⁄ r potential, which is continuous everywhere except the origin. The electric field is not continuous across an idealized surface charge, but it is not infinite at any point. Therefore, the electric potential is continuous across an idealized surface charge. An idealized linear charge has ln(r) potential, which is continuous everywhere except on the linear charge.

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  1. S

    Calculating Kinetic Energy of Particle B Using Electrical Potential

    Particles A (of mass m and charge Q) and B (of mass m and charge 5 Q) are released from rest with the distance between them equal to 0.4939 m. If Q= 31 uC, what is the kinetic energy of particle B at the instant when the particles are 2.4939 m apart? Answer in units of J. I know that the...
  2. J

    What is the dielectric constant of the material between the plates?

    electrical potential help..urgent! 1) A parallel-plate capacitor is made of two flat metal plates pressed against a thin slab of dielectric material. The capacitor is connected to a power supply, and a potential difference of 100 V is applied to the plates. With the power supply disconnected...
  3. U

    What is the relationship between electrical and gravitational potential energy?

    I have no idea what principles i am supposed to use in this question? Could someone show me how to do this question please? Thanks :smile: Calculate the electrical potential energy of two protons separated by 1 nm, and compare it with their gravitational potential energy. Estimate how heavy...
  4. K

    Electronics - Potential Difference & Electrical Potential

    1. Through what potential difference would an electron need to be accelerated for it to achieve a speed of 50.0% of the speed of light, starting from rest? The speed of light is c = 3.00 108 m/s. >> I'm really not too sure what to do with this problem. I took .50*3.00e8 and got 1.50e8...
  5. B

    Need Help On Electrical Potential Energy

    I need help on these ?'s. They are very confusing to me. Can someone please help me. -Here they are: >Two charges are located along the x-axis. ONe has a charge of 6.4 micro C, and the second has a charge of -3.2 micro C. If the electrical potential energy associated with the pair of...
  6. G

    Kinetic Energy from Point A to B: Electron Volts

    point a is at a potentiall of +290...point b is at potential of -220...helium nucleus contains 2 neutrons and 2 protons...neutrons are electrically neutral...what kinetic energy does particle have after accelerating from rest at point a to b...in electron volts
  7. Q

    How is electrical potential transmitted through an electric circuit

    My question is how is electrical potential actually transmitted through an electric circuit. A charge (i.e. and electron) is moved through an magnetic field (as in a generator), the particle gains electric potential due to the work performed on it in the generator. This potential is then used...
  8. G

    Electric Potential in a Region: Is it Zero or Nonzero?

    The potential is constant throughout a given region of space. Which of the following statements is true? Be sure you can justify your answer. The electric field may have places where it is zero, and places where it is nonzero in this region. The electric field is nonzero in this region...
  9. S

    Why Does the Equation for Electrical Potential Energy Include a Factor of 1/2?

    In Feynmann's Lectures on Physics, many of you will have come across the chapter on electrostatic energy. I wonder if someone could explain to me why we have the factor 1/2 in the equation: U = \frac{1}{2} \int \rho \phi dV where \rho is the charge density of one distribution of...
  10. E

    Electrical Potential Energy Problem

    Hello, I've been trying and trying to do this problem for quite a while now, and I can't seem to get an answer which agrees with the book. I figured that one metal sphere would then end up with a charge of 10^13 electrons (so I multiplied that by 1.60x10^-19 to get the charge of all the...
  11. M

    What is the total electrical potential energy

    Suppose two protons are a small distance 2.5x10^-15m apart. What is the total electrical potential energy this system?
  12. G

    Electrical potential and surface curvature

    Electrical potential is constant everyplace on the surface of a charged conductor. Also, on the surface of an irregularly-shaped conductor, the charge density is high in convex regions with small radius of curvature (especially, for example, at sharp points), and low in regions of large...
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