ch33_nrqd


 * __ Chapter 33 Electric Fields and Potential __**

__**Electric Fields**__

The space around every electric charge is filled with an electric field which is a kind of aura that extends through space. An electrical field has both magnitude and direction. Its magnitude is measured by its effects on changes located in the field. The direction of the field is the direction of the electrical froce on a small possitive test charge placed at that point. The field is strongest where the force is the greatest on the test charge and visa versa.



Much like the moon and earth rotate around the sun, Electrons orbit around electrons following a similar path.


 * __Electric Field Lines__**

Since an electric field is a vector quantity (Magnitude and Direction), it can be represented by vectors, or field lines. Where the lines are farther apart, the field is considered weaker, and where their closer together, the field is sonsidered stronger. The direction of the lines point away from the possitively charged particle and aim towards the negatively charged particle.



This diagram shows how the the charges leave the possitively charged object and go into the negatively charged one. However if the two charges are both the same, like in the picture on the right, then the lines will repel away from each other. Likes charges repel, opposites charges attract.

__**Electric Shielding**__

When a car is struck by lightning, everything inside the car remains unharmed. This is because the electrons from the lightning bolt mutually repel and spread over the outer metal surface of the car. Since the electric field inside the car cancels out to zero, even though the field outside the car is very strong, cars are a relatively safe place to be during a lightning storm.



The charge is greatest at the corners or points of certain objects like shown above. Whenever the object doesnt have any corners, like the cirlce above, they are equally spaced out. Static charges scattered all over the surface on the conductors, which causes the electric fields inside the objects to be zero.

__**Electric Potential Energy**__

Potential energy is the energy of position, ususally related to the relative position of two things. Like in the diagram below, potential energy is the energy waiting to be released into kinetic energy.

Potential energy in a magnetic field is done by forcing two like charges together or by pulling two different charges away from each other. Similar to how work is done in a spring, work is done in pushing the charge against the electric field. The energy change now posseses based on location is called electric potential energy.

__**Electric Potential**__

Electric potential is electrical potential energy per coulomb at a location in an electric field ehich is measured in volts. Usually refered to voltage. A good example of how electric potential works is a charged balloon. Even though the voltage is high, the electric potential energy is very small due to the little change produced. A high voltage requires a lot of energy only if there is a large charge involved.

The equation to represent electric potential is described by the following: Electric Potential= __Electric Potential Energ__ Charge

Since potential energy is measured in joules and charge is measured in coulombs, the new equation is expressed as the following:

1 Volt= __Joule__ Coulomb

__**Electric Energy Storage**__

A capacitor is a common device that is capable of storing electrical energy. A charged capacitor is discharged when a conducting path is provided between the plates. The energy stored in a capacitor comes from the work required to change it. Energy stored in a capacitor is energy stored in an electric field. The charging process in complete when the potential difference between the plates equals the potential difference between the battery terminals. If the battery has high voltage in large, close plates, then a greater charge is stored.

Nick and Quinn