Physics 7B - Chapter 23: Electric Potential

Potential Energy

stored energy of an object because of it’s position, state, or structure

Electric Potential Energy

Stored energy that a charge has because of it’s position within an electric field

Change of Potential Energy

\Delta U=-W=\Delta K

Electric Potential

V_{a}=\frac{U_{a}}{q}

aka potential, electric potential energy per unit charge at a point, relative to some reference.

The amount of work needed per unit charge to bring a test charge from infinity to a point in the electric field.

Definition of Potential Difference

\Delta V=\frac{\Delta U}{q}=-\frac{W}{q}  

aka Voltage, measure of how much potential energy an electric charge can acquire (if pos) or how much work a particular charge can do (if neg) 

Which direction does a pos/neg charge move in an electric field?

Pos Charge: moves from high to low potential

Neg Charge: moves from low to high potential

Relationship between potential difference and electric field

\Delta V=-\int_{a}^{b}\overrightarrow{E}\cdot\overrightarrow{dl}

Formula is just negative integral form of work but with E instead of F so we have V in Joules per Coulomb

Potential Difference for uniform electric field

\Delta V=-Ed\cos\theta