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Physics Essential Standards Covered:
Physics Essential Standards Covered:
Phy.3.1.5
Compare work done on an object by lifting (changes in location in a gravitational field) to work done on a charged particle by pushing it against the electric field of a charged object – both positive and negative.
Define electric potential energy as the energy of a charge based on its location and distinguish electric potential (voltage) as being the same for all charges.
Conclude that a gravitational field is always in one direction while electric fields have two possible directions; by convention, the direction is determined by the direction of force on a positive test charge – away from (out of) a positive charge and toward (into) a negative charge.
Key Vocabulary:
Key Vocabulary:
Electric Potential
Work
Voltage
Electric Fields
Charges
Suggested Reading:
Suggested Reading:
Lesson:
Lesson:
Electric Potential: is the difference in potential energy per unit charge between two locations in an electric field. AKA: The Voltage!
Electric Potential: is the difference in potential energy per unit charge between two locations in an electric field. AKA: The Voltage!
Electric fields generate forces on electric charges. The energy associated with a charge in an electric field can be thought of in terms of the work needed to move the charge.
Electric fields generate forces on electric charges. The energy associated with a charge in an electric field can be thought of in terms of the work needed to move the charge.
We can think about electric potential energy, just like gravitational potential energy.
We can think about electric potential energy, just like gravitational potential energy.
Gravitational Potential Energy and Work
Gravitational Potential Energy and Work
If you were to lift an object applying a force over a certain displacement you are doing work increasing the potential energy of the object you are moving.
If you were to lift an object applying a force over a certain displacement you are doing work increasing the potential energy of the object you are moving.
Electric Potential Energy and Work
Electric Potential Energy and Work
The same thing can be said with a single charge. If the charge is moved (usually do to forces of the electric field present) over a certain displacement, work was done to move the charged particle. Doing the work and moving the particle causes the electric potential energy to increase, just like the gravitational potential energy!
The same thing can be said with a single charge. If the charge is moved (usually do to forces of the electric field present) over a certain displacement, work was done to move the charged particle. Doing the work and moving the particle causes the electric potential energy to increase, just like the gravitational potential energy!
The Electric Potential is equal to the electric potential energy divided by the charge present in the field.
The Electric Potential is equal to the electric potential energy divided by the charge present in the field.
Remember!
Remember!
Electric Potential = Voltage
Electric Potential = Voltage
According to this formula, the voltage at a given point is equal to the electric potential energy of a small test charge at that location divided by the value of the charge itself.
According to this formula, the voltage at a given point is equal to the electric potential energy of a small test charge at that location divided by the value of the charge itself.
As one might imagine, the electric potential between two points in an electric field may vary. Accordingly, the difference in electric potential from one point to another is known as the potential difference. This potential difference is often called a voltage.
As one might imagine, the electric potential between two points in an electric field may vary. Accordingly, the difference in electric potential from one point to another is known as the potential difference. This potential difference is often called a voltage.
Electric Potential = Voltage = Potential Difference
Electric Potential = Voltage = Potential Difference
I know what you are thinking! Why can't they just stick with one name!
I know what you are thinking! Why can't they just stick with one name!
How is the Potential Difference related to the electric field?
How is the Potential Difference related to the electric field?
E = electric field
E = electric field
V = potential difference
V = potential difference
d = distance between parallel plates
d = distance between parallel plates
Let's do a problem!
Let's do a problem!
If the potential difference between the two parallel plates is 54 V and the distance between plates is 0.2m. What is the magnitude of the electric field?
If the potential difference between the two parallel plates is 54 V and the distance between plates is 0.2m. What is the magnitude of the electric field?
E = V/d = 54V/0.2m
E = V/d = 54V/0.2m
E = 270 V/m
E = 270 V/m
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