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Electric Potential

Posted: March 16th, 2012, 3:48 pm
Objects naturally move from high potential energy to low potential energy.
Work is required to move an object from low to high potential energy.

Gravitational Potential Energy: the work required to move a mass against a gravitational field
Electric Potential Energy: the work required to move a charge against an electric field

For parallel plates:
The electric field between two parallel plates is uniform, so the force to move a charge within that field will be constant.

W = EqΔx

For point charges:
The closer to the point charge, the stronger the electric field. Thus, the force to move a charge within the e-field is NOT constant.

W12 = ΔPE12 = $kQq(\frac{1}{r_2}-\frac{1}{r_1})$
∞ is our reference point

W = PE = $kQq(\frac{1}{r_2}-\frac{1}{\infty })$ = $\frac{kQq}{r}$

Electric Potential (V):
The work per unit charge required to bring a charge from a very large distance (reference point = ∞) to a particular point in an electric field

$V=\frac{kQ}{r}$

units: J/C = Volt