Transcript What is an electric field?

Conceptual Physics: Electricity:
What is an electric field?
- The space surrounding a charged object is affected by the presence of the charge;
an electric field is established in that space. A charged object creates an electric field
How do different electric fields interact?
These two examples are when a test charge is the same sign as that of the electric field.
These two examples are when a test charge is the opposite sign as that of the electric field.
How do charged objects create electric potential?
Gravitational Potential
V.s
Electric Potential
1) Mass - a property of the object experiencing the gravitational field.
2) Height - the location within the gravitational field.
Electric Potential
1) Electric charge - a property of the object experiencing the electrical field.
2) Distance from source - the location within the electric field.
PE = Potential Energy
Q = Charge
While electric potential energy has a dependency upon the charge of the object experiencing the electric field,
electric potential is purely location dependent. Electric potential is the potential energy per charge.
What is the electric potential difference?
Consider the task of moving a positive test charge within a uniform electric field from location A to location B as shown in the diagram below. In moving the charge against the electric field from
location A to location B, work will have to be done on the charge by an external force. The work done on the charge changes its potential energy to a higher value; and the amount of work that is
done is equal to the change in the potential energy. As a result of this change in potential energy, there is also a difference in electric potential between locations A and B.
This difference in electric potential is represented by the symbol V and is formally referred to as the electric potential difference.
Relation to circuits
Relationship to batteries
What is a circuit ?
Consider the following situation. There are two metal plates parallel to each other and each being charged with an opposite type of charge - one being positive and the other being negative. This
arrangement of charged plates would create an electric field in the region between the plates that is directed away from the positive plate and towards the negative plate. A positive test charge
placed between the plates would move away from the positive plate and towards the negative plate.
Now suppose that the two oppositely charged plates are connected by a metal wire. What would happen? The wire serves as a sort of charge pipe through which charge can flow.
An example of a simple circuit
The fact that the light bulb lights and remains lit is evidence that charge is flowing through the light bulb filament and that an electric circuit has been established.
How can we make a circuit? What's required?
What is a light bulb?
The difference between a successful and not successful circuit.. closing the loop!
Electrons doing Work!
An electrical circuit is simply an energy transformation tool. Energy is provided to the circuit by an electrochemical cell, battery, generator or other electrical energy source. And energy is delivered
by the circuit to the load at the location of the load. The rate at which this energy transformation occurs is of great importance to those who design electrical circuits for useful functions