Electric Potential and Potential Difference
This page introduces the concepts of electric potential and electric potential difference in physics, providing essential formulas and explanations.
Electric potential is defined as a scalar quantity associated with points in space, used to understand an electric field's potential energy without placing a charge in the field. It is symbolized by V and measured in Joules per Coulomb.
Vocabulary: Electric potential - A scalar quantity representing the potential energy per unit charge at a point in an electric field.
The relationship between electric potential energy (UE) and charge (q) is given by the formula:
UE = qV
For point charges, the electric potential is calculated using the formula:
V = kQ/r
Where k is Coulomb's constant, Q is the charge, and r is the distance from the charge.
Definition: Electric potential difference, also known as voltage, is the difference in electric potential between two points in an electric field.
Key points about electric potential difference:
- It is independent of the chosen sequence
- Symbolized by ΔV and measured in volts (Joules/Coulomb)
- The change in electric potential energy is related to potential difference by ΔUE = qΔV
Highlight: Positive charges have positive electric potential energy (UE > 0), while negative charges have negative electric potential energy (UE < 0).
The electric potential energy at a point A (UEA) represents the work required to move a charge from a reference point (usually infinity or where U = 0) to location A.
Example: When calculating electric potential energy between two point charges, the formula UE = kq1q2/r is used, where q1 and q2 are the charges and r is the distance between them.
It's important to note that while you can choose the reference point for electric potential arbitrarily, the difference in potential (voltage) is what matters in calculations.
Vocabulary: Conservation of energy - The principle that energy cannot be created or destroyed, only converted from one form to another.
The work-energy theorem relates the work done on a charge to its change in electric potential energy. In an electric field, the work done to move a charge between two points equals the negative change in its electric potential energy.
