Electric Potential 2

Electric Potential

Energy  Capacity

to do work

Remember this Formula…. Some representation might change…

The Gravitational Analogy Revisited  defined

as the energy stored in an object due to its vertical position above the Earth

The Gravitational Analogy Revisited  gravitational

potential - the potential energy per kilogram  Gravitational potential energy depends upon object mass and object height. Gravitational potential describes the affects of a gravitational field upon objects which are placed at various locations within it.

If gravitational potential is a means of rating various locations within a gravitational field in terms of the amount of potential energy per unit of mass, then the concept of electric potential must have a similar meaning.

Consider this setup

The amount of force involved in doing the work is dependent upon the amount of charge being moved

As the monkey does work on the positive charge, he increases the energy of that charge. The closer he brings it, the more electrical potential energy it has. When he releases the charge, work gets done on the charge which changes its energy from electrical potential energy to kinetic energy.

Electric Potential energy depends:  1)

Electric charge - a property of the object experiencing the electrical field, and  2) Distance from source - the location within the electric field How is this the same with the Gravitational Potential?

Electric Potential Energy In

order to bring two like charges near each other work must be done. In order to separate two opposite charges, work must be done. Remember that whenever work gets done, energy changes form.

Electric Potential Energy defined

as the capacity for doing work which arises from position or configuration. In the electrical case, a charge will exert a force on any other charge and potential energy arises from any collection of charges

Electric Potential Energy

Work done

Change W to U to represent Electric Potential Energy

Electric Potential Energy

 U=Potential

Energy  K=Coloumb’s constant  q=charges  Q=source charge  r=distance

Electric Potential

 U=Potential  Q=charge

Energy

Questions  1.

The quantity electric potential is defined as the amount of _____.  a. electric potential energy b. force acting upon a charge  c. potential energy per charge  d. force per charge

Questions  2.

Complete the following statement:  When work is done on a positive test charge by an external force to move it from one location to another, potential energy _________ (increases, decreases) and electric potential _________ (increases, decreases).