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    Electricity Electric Potential

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    lumine0755
    1. Electric potential is a measure of electric potential energy per unit charge at a point in an electric field. It is defined as the work required to move a unit positive charge from a reference point to that location. 2. The electric potential at a point due to a point charge Q is directly proportional to Q and inversely proportional to the distance r from the point charge. 3. A difference in electric potential between two points causes electric charges to move - this movement of charges constitutes an electric current.

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    Electricity Electric Potential

    Uploaded by

    lumine0755
    5 views13 pages
    1. Electric potential is a measure of electric potential energy per unit charge at a point in an electric field. It is defined as the work required to move a unit positive charge from a reference point to that location. 2. The electric potential at a point due to a point charge Q is directly proportional to Q and inversely proportional to the distance r from the point charge. 3. A difference in electric potential between two points causes electric charges to move - this movement of charges constitutes an electric current.

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    2. Electricity Electric Potential

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    1. Electric potential is a measure of electric potential energy per unit charge at a point in an electric field. It is defined as the work required to move a unit positive charge from a reference point to that location. 2. The electric potential at a point due to a point charge Q is directly proportional to Q and inversely proportional to the distance r from the point charge. 3. A difference in electric potential between two points causes electric charges to move - this movement of charges constitutes an electric current.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    5 views13 pages

    Electricity Electric Potential

    Uploaded by

    lumine0755
    1. Electric potential is a measure of electric potential energy per unit charge at a point in an electric field. It is defined as the work required to move a unit positive charge from a reference point to that location. 2. The electric potential at a point due to a point charge Q is directly proportional to Q and inversely proportional to the distance r from the point charge. 3. A difference in electric potential between two points causes electric charges to move - this movement of charges constitutes an electric current.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
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    Make Each Day

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    Be a blessing everyday!
    Electricity
    (Electric Potential)
    MELCs
    1. Determine the electric potential function at any point due
    to highly symmetric, continuous charge distributions.
    2. Solve problems involving electric charges, dipoles, forces,
    fields, and flux.
    3. Solve problems involving electric potential energy and
    electric potentials.
    Potential difference causes an electric _______.
    current

    To understand potential difference,

    we need to understand ELECTRIC POTENTIAL.


    To understand electric potential,

    we need to understand WORK.


    a form of energy transfer
    When work is done on an object, the
    energy of the object changes:

    W = ΔE
    W = ΔKE W = ΔPE
    Electric PE
    • energy a charge has due to its position in the
    electric field of other charges:

    EPE = Vq
    EPE = electric potential energy of charge q (SI unit is J)
    V = electric potential at the location of q (SI unit is J/C or V)
    q = charge (SI unit is C)
    Electric Potential
    • at a given point, is the electric potential energy of a small
    charge q situated at that point divided by the magnitude of
    the charge:

    V = EPE/q
    • For a point charge Q,

    V = kQ/r
    V = electric potential at a distance r from Q
    Q = source charge
    r = distance from Q
    At a distance r from a point charge Q, the electric potential is:
    V = kQ/r
    V = electric potential at a distance r from Q
    Q = charge
    r = distance from Q

    Thus, at point A, the electric potential is VA = kQ/r.

    Q r A

    And a test charge at that point will have an electric


    potential energy of EPE = VA q.

    Q r q
    If Q is positive, and if we consider another point from Q (point B), then we
    have two points at different electric potentials:

    Point at higher Point at lower


    electric potential electric potential
    Q B A

    Because of the electric potential difference between A and B, the electric


    field between A and B will cause a test charge q to move from B to A:

    Q q A

    Thus, electric potential difference causes electric charges to move.


    And when charges move, there is electric current.
    Sample Problem
    What is the potential on the surface of
    a Au nucleus? (R=6.2 fm, Z=79)

    By considering the nucleus as a point charge and r=R:


    V = kQ/r
    = (9 x 109 N.m2/C2)(79)(1.6 x 10-19 C)/(6.2 x 10-15m)
    = 183 x 105 V
    = 1.8 x 107 V
    The PD between the ground and a cloud in a
    particular thunderstorm is 1.2 x 109 V. What is the
    magnitude of the change in EPE of an electron that
    moves between these points?

    ΔV = ΔEPE/q
    ΔEPE = ΔVq
    = (1.2 x 109 V)(1.6 x10-19 C) Using the absolute value of the electron’s charge

    = 1.92 x 10-10 J
    = 1.9 x 10-10 J

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