University:
Kentucky State University
Course:
PHY 212 | General Physics II
Academic year:

2020
Views:

404

Pages:

3
Author:

Sean Horton

Last lecture: brush up! 1) Potential energy vs. electric potential We define electric potential V via potential energy U needed to move charge q: U  qV U  U  q (V  V ) unit of electric potential: f 2) Relation between electric potential and electric field i f i f Vf  Vi    E  d i 3) Electric Potential of a point charge: 1 q V r  . 40 r 4) Potential energy of two point charges q1q 2 1 q1q 2 U  r12   k  r12 40 r12 5) The Electron Volt Only valid for a point charge! 1 eV= 1.6  10 J -19 J/C = V (Volt) 6) Potential Gradient (Determining Electric Field from Potential) V E r An electron volt (eV) is the energy acquired by a particle of charge e when it moves through a potential difference of 1 volt. Today’s agenda: Electric potential & Electric potential energy. You must be able to calculate the electric potential for a point charge, and use the electric potential in work-energy calculations. The electron volt. You must be able to use the electron volt as an alternative unit of energy. Equipotentials. You must be able to sketch and interpret equipotential lines and surfaces. Potential gradient. You must be able to calculate the electric field if you are given the electric potential. Potentials due to charged conductors. You must be able to use what you have learned about electric fields, Gauss’ law, and electric potential to study conductors in electrostatic equilibrium. Electric potential of a charge distribution. You must be able to calculate the electric potential for a charge distribution. Electric potential V of charge distributions 1 Collection of charges: VP  40 qi i r . i P is the point at which V is to be calculated, and ri is the distance of the ith charge from P. Charge distribution: (line charges, sheet charges, spheres, cylinders, etc) dq 1 dq V .  40 r Potential at point P. P r