Electric Field Due to a Point Charge

 , where:

E = Electric Field (N/C)

 = Pi

 = Electric Constant (Fa/m)

q = Electric charge of particle (C)

r = Distance from particle (m)

Electric Potential Energy

 , where:

E = Potential Energy (J)

q = Electric Charge of Body (C)

V = Electric Potential or Voltage (V)

Electric Susceptibility of a Material

 , where:

 = Electrical Susceptibility

 = Relative Permittivity (Material Property)

Electron Charge

 , where:

q = Charge of an electron (C)

Energy Stored in a Capacitor

 , where:

E = Energy Stored (J)

C = Capacitance (Fa)

V = Voltage (V)