1 / 9

Electric Energy

Electric Energy. Electrical Potential Energy. Potential energy is the negative of the work done by conservative forces. Potential energy D U = - W con Electrical work is done by the Coulomb force. Electrical potential energy. A charge in an electric field is subject to a force.

bao
Download Presentation

Electric Energy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Electric Energy

  2. Electrical Potential Energy • Potential energy is the negative of the work done by conservative forces. • Potential energy DU = -Wcon • Electrical work is done by the Coulomb force. • Electrical potential energy

  3. A charge in an electric field is subject to a force. Moving the charge against the field requires work. The state of the charge is changed to increase the potential energy. q q Changing State d E F

  4. The potential energy is expressed as a difference of the energy of two states. The electric potential can be expressed with respect to a test charge. q q Potential Difference DU d E F

  5. Coulomb’s law is mathematically similar to gravitational force. Define potential energy similarly Point charge Q Test charge q Apply the definition of the electric potential. Like gravity zero is at infinity. Point Potential

  6. Potential Curve • The point potential can be attractive or repulsive. • Attraction like gravity

  7. The zero of potential energy is arbitrary. U can be defined, but DU is what really matters. Compare energy to work We can measure the change in electric potential V. No experiment reveals the specific value q Arbitrary Zero Vf E V = 0

  8. The electric force is conservative. Energy is conserved Independent of the experiment Suppose that charge were not conserved. An experiment would be able to cause some charge to vanish Loss of specific amount of potential energy Inconsistent with energy conservation q Charge Energy Vf E V = 0

  9. Conservation of Charge • The arbitrary zero of the potential was the heart of the preceding contradiction. • To have an electric potential independent of the choice of zero, and be conservative, requires charge conservation. • This is an example of symmetry in physics. next

More Related