Electric Potential

• The positive charges, being close together, possess what?

  High Potential Energy
• As the positive charges accelerate away from each other, the potential energy is converted to kinetic energy and work is done by electric field.
• After grounding, the potential of a charge (ex. negative charge) rises to zero.
• Positive charges move from a place of high electric potential (or near a positive charge) to a place of low electric potential (or near a negative charge)
• ______ of a charged body is equal to the amount of work done by an external agent to bring a unit positive charge from a point of zero potential to the body.

  Electric Potential (V)
• What is the unit of electric potential?

  Volt or Joules/Coulomb
• It is the work done in carrying a unit positive from a point of lower potential to a point of higher potential.

  Electric Difference
• It is a three dimensional surface on which the potential is the same at every point.

  Equipotential Surface
• Since the potential energy does not change as a charged is moved over an equipotential surface, the electric field cannot do work on such charge.
• The work is zero if the force and displacement are perpendicular to each other. Thus, the electric field lines and equipotential surfaces are always perpendicular to each other.
• This is important in situations where there are changes in a certain quantity like temperature gradient, etc.

  Gradient
• Equipotential lines are drawn in an electric field so that all points in the said line are at the same potential.
• The equipotential surfaces around a point change can be represented by concentric equipotential spheres.
• Electric field lines or lines of force are always directed away from the positive charge going toward the negative charge.
• The electric field line is also known as line of force.
• A device that have the capability of storing charges temporarily.

  Capacitor
• This device consists of two conducting objects thata re near each other but not touching.

  Capacitor
• The capacity of the capacitor to store charges depends on the voltage or the potential difference of the objects.
• If two identifcal spheres are at different voltages, the one with the higher voltage stores more charges than the one with the lower voltage.
• If the voltage of an object is double, the amount of charge on it also doubles.
• It is defined as the ratio of the magnitude of the charge on either plate to the potential difference between them.

  Capacitance
• The maximum charge is then reached by the plates that is, when the voltage between plates becomes equal to V of the battery the electron flow ceases.
• SI unit of capacitance is Farad (F) or coulomb/volt.
• It is the most common type of capacitor. Capacitors may be, connected to series and parallel or both.

  Parallel-Plate Capacitor
• It consist if two metal plates separated by an insulator.

  Parallel-Plate Capacitor
• In a parallel-plate capacitor if the plates are exactly projected on each other, if is assumed that the electric field between the plates is uniform.
• When the plates are sufficiently close enough to each otherz the fringing of the electric field lines may be disregarded.
• Capacitors are also known as condensers.
• The potential difference across each capacitor is the same as the potential difference across the combination.
• When capacitors are connected in parallel, all the positive plates are connected to the positive terminal of the battery, while the negative plates are connected to the negative terminal of the battery.
• It is the sum of the individual capacitance. In mathematically, Ctotal = C1 + C2 + C3 …

  Total capacitance
• The total potential difference (Voltage) between their plates are equivalent and are equal to the total Voltage. In equation, Vtotal = V1 = V2 = V3…