Physics 102 Chapter 17 Lecture Notes
Lecture 2
Review Electric Potential Energy and Potential Difference
We defined the Electric Field E as:
Force/unit charge
-or-
E = F/q
This means that if we have a charge q, in an electric field E,
The force F on q at position (x,y) = E(x,y) * q
Similarly, we define the Electric Potential V (not a vector, just a number), as:
Electric potential energy/unit charge
-or-
Va = PEa/q
This means that if we have a charge q, in an electric field at position “a”
The electric potential energy of q at position “a” = Va * q
This is just like saying that if we have a mass m at a height of h,
The gravitational potential energy of m at position h = mgh
Definition of electric potential energy:
Definition of the electric potential and potential difference:
Exercise 17-2 Electron in a TV picture tube
a) Change in electric potential energy
b) Speed of the electron as a result of the change in PE
17-2 Electric Potential and the Electric Field
Obtaining the relationship from Work:
General relationship between the electric potential and the electric field:
17-3 Equipotential Lines