potential difference

(noun)

The difference in potential energy between two points in an electric field; the difference in charge between two points in an electrical circuit; voltage.

Related Terms

  • terminal voltage
  • particle accelerator
  • electron volt
  • potential energy
  • kinetic energy
  • electric field
  • electromotive force

Examples of potential difference in the following topics:

  • Electric Potential Energy and Potential Difference

    • Electric potential energy results from forces between charges; potential difference is the energy needed to move a charge from point A to B.
    • Potential difference , or voltage, is the difference in electric potential energy between two points.
    • Potential difference is independent of path taken from one point to another, and may be measured by any of a number of instruments .
    • When a charge q moves from point A to point B, the potential difference is independent of path taken.
    • A brief overview of electric potential difference and electric potential energy for beginning physics students.
  • Van de Graff Generators

    • A Van de Graaff generator is a device that can be used to separate charges and create potential differences in the range of megavolts.
    • Using a moving belt, it can create extremely high potential differences.
    • In this figure, a high, positive DC potential is applied to the upper roller.
    • Final potential is proportional to the size of the sphere and its distance from the ground.
    • Numbers in the diagram indicate: 1) hollow metal sphere; 2) upper electrode; 3) upper roller (for example an acrylic glass); 4) side of the belt with positive charges; 5) opposite side of the belt with negative charges; 6) lower roller (metal); 7) lower electrode (ground); 8) spherical device with negative charges, used to discharge the main sphere; 9) spark produced by the difference of potentials
  • Uniform Electric Field

    • Uniformity in an electric field can be approximated by placing two conducting plates parallel to one another and creating a potential difference between them.
    • where E is the field, Δ is the potential difference between the plates, and d is the distance between the plates.
    • For the case of a positive charge q to be moved from a point A with a certain potential (V1) to a point B with another potential (V2), that equation is:
    • The difference (V2-V1) can also be represented as ∆V or VAB.
    • In this image, Work (W), field strength (E), and potential difference (∆V) are defined for points A and B within the constructs of a uniform potential field between the positive and negative plates.
  • Potentials and Charged Conductors

    • Electric potential within a charged conductor is equal to zero, but can be calculated as a nonzero value outside of a charged conductor.
    • This can be proven by relating electric field and potential.
    • Given that work is the difference in final and initial potential energies (∆U), we can relate this difference to the dot product of force at every infinitesimal distance l along the path between the points within the conductor:
    • Rewriting U as the product of charge (q) and potential difference (V), and force as the product of charge and electric field (E), we can assert:
    • Thus we can conclude that, given that the electric field is constantly 0 for any location within the charged conductor, the potential difference in that same volume needs to be constant and equal to 0.
  • Relation Between Electric Potential and Field

    • Electric potential and field are related in that potential is a property of the field that describes the field's action.
    • The relationship between electric potential and field is similar to that between gravitational potential and field in that the potential is a property of the field describing the action of the field upon an object (see ).
    • They share a common factor of inverse Coulombs (C-1), while force and energy only differ by a factor of distance (energy is the product of force times distance).
    • Thus, for a uniform field, the relationship between electric field (E), potential difference between points A and B (Δ), and distance between points A and B (d) is:
    • The presence of an electric field around the static point charge (large red dot) creates a potential difference, causing the test charge (small red dot) to experience a force and move.
  • Energy Conservation

    • This phenomenon can be expressed as the equality of summed kinetic (Ekin) and electric potential (Eel) energies:
    • In all cases, a charge will naturally move from an area of higher potential energy to an area of lower potential energy.
    • Throughout this time, the sum of potential and kinetic energies remains constant.
    • where V is the potential difference, k is a constant, q0 is a test charge, q is another charge, and r is the distance between the charges.
    • In both instances, the particle in motion goes from a higher to a lower potential energy state.
  • Electric Potential in Human

    • As a result, a cell can contain a concentration of a given ion that differs from that which exists outside.
    • Thus, a potential, called the resting potential, is created on either side of the membrane.
    • Potentials can change as ions move across the cell membrane.
    • This impulse is passed through the axon, a long extension of the cell, in the form of an electrical potential created by differing concentrations of sodium and potassium ions on either side of a membrane in the axon .
    • This impulse is passed through the axon, a long extension of the cell, in the form of an electrical potential created by differing concentrations of sodium and potassium ions on either side of a membrane in the axon.
  • Electric Potential Due to a Point Charge

    • Recall that the electric potential is defined as the electric potential energy per unit charge
    • The electric potential tells you how much potential energy a single point charge at a given location will have.
    • The potential difference between two points ΔV is often called the voltage and is given by
    • The potential at infinity is chosen to be zero.
    • Earth's potential is taken to be zero as a reference.
  • What is Potential Energy?

    • Potential energy is the energy difference between the energy of an object in a given position and its energy at a reference position.
    • This work is stored in the force field as potential energy.
    • The more formal definition is that potential energy is the energy difference between the energy of an object in a given position and its energy at a reference position.
    • More specifically, every conservative force gives rise to potential energy.
    • For example, the work of an elastic force is called elastic potential energy ; work done by the gravitational force is called gravitational potential energy; and work done by the Coulomb force is called electric potential energy.
  • Superposition of Electric Potential

    • We've seen that the electric potential is defined as the amount of potential energy per unit charge a test particle has at a given location in an electric field, i.e.
    • We've also seen that the electric potential due to a point charge is
    • with the difference that the electric field drops off with the square of the distance while the potential drops off linearly with distance.
    • So for example, in the figure above the electric potential at point L is the sum of the potential contributions from charges Q1, Q2, Q3, Q4, and Q5 so that
    • The summing of all voltage contributions to find the total potential field is called the superposition of electric potential.
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