Electric Potential Energy and Electric Energy

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Electric Potential Energy and Electric Energy

• Monkemeier
• Unit 7 Electrostatics

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Electric Potential Energy

• The energy that a charged particle has due to its
  location within an electric field.

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The energy that a charged particle has due to its
location within an electric field.

• What does this mean????
• Look at the diagram to the right.

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Which Position has the Highest Electrical
Potential Energy?

• What if you had a NEGATIVELY CHARGED PARTICLE at
  Positions A, B, and C.
• At which positions would the negatively charged
  particle have the MOST Electrical Potential
  Energy?
• Answer Position A. WHY? Because like charges
  repel and it would take work to keep the
  negatively charged particle at A. C is farthest
  away and that is a more natural position.

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How do you determine which position would have
the MOST EPE?

• First examine the charges on the two objects.
• Then decide if the two objects would repel (then
  the closest position away has more EPE) or
  attract (then the farthest position away would
  have more EPE)
• Keep in mind that WORK is needed to push toward
  or pull away the charge!

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TRY AGAIN!

• The charged object negatively charged and it is
  brought near, but NOT touching the positive
  charge in the center.
• At which position, A or B would the charged
  particle have the MOST EPE?
• EXPLAIN WHY using the concepts of work and the
  fundamental rule of electrostatics.

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Answer

• Position B would have the most EPE because
  oppositely charged particles attract and the
  negatively charged particle would WANT to be as
  close to the center positive charge as possible.
• It would take a pull (force) to bring the charge
  at a greater separation distance B.
• Work change in EPE!

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Does Work Change in Electric Potential Energy?

• YES!
• Work F x d D Electric Potential Energy
• Remember that it took a PUSH through a distance
  or a PULL through a distance to move a given
  charge away from another charge.
• When work is performed on a charged object, the
  charged object GAINS EPE!

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Electric Potential

• Electric Potential Energy per unit charge at a
  location in an electric field measured in volts
  and often called voltage.
• Joules / Coulomb Volt

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Electric Potential

• Charged objects have different amounts of
  Electric Potential due to their magnitude of
  charge and their EPE.
• Reminder that EPE is related to the separation
  distance between the charges and the amount of
  push or pull it took to get that charged particle
  to that location.

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Think Electric Potential
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WHY ELECTRIC POTENTIAL - The state for which
flow of charge between two charged bodies can
take place is called electric potential.
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Electric Potential helps us predict!

• The state for which flow of charge between two
  charged bodies can take place is called electric
  potential.