Electrostatic Potential and Capacitance – Notes
Potential energy in an external field
Electrostatic potential energy of a system of charges is expressed as:
U = U12 +U23+ +U13
Electron volt is defined as the kinetic energy gained by an electron when accelerated under a potential difference of one volt.
Electrostatic potential energy in the system of two charges is expressed as:
U = q1 V(r1) + q2 V(r2) + 1/4πε0 (q1 q2/r12)
The electrostatic potential energy of the system can be written as:
= – (pE COS ⍬) – 1/4πε0 (q2/2a)
Electrostatic potential and potential due to a point charge
The electric potential (V) at any point in the electric field of a charge configuration is equal to the work done to bring a unit positive charge from infinity to that point in the electric field.
The electric potential (V) at a point is expressed as: V= 1/4πε0 (Q/r)
The electric potential V is a scalar quantity.