AP Physics B Notes: Ch 16: Electric Potential Name: Excess Charges on Conductors Where does the excess charge reside on a charged conductor? What conditions would produce high positive electrical potential energy? How does this help lightening rods to work? What conditions would produce low negative electrical potential energy? How would you get zero electrical potential energy? Electric Field Inside a Conductor Why is the field on the inside of an isolated conductor necessarily zero? Electric Potential What do we commonly call electrical potential? Draw an isolated conductor in an electric field, and show how the charge is distributed so as to nullify the external field. Electrical Potential and Potential Energy Electric Potential Energy Definition: Electrical Potential and Potential Energy Positive charges like to their potential (ΔV 0) Negative charges like to their potential. (ΔV 0) AP Physics 1 Chapter 16: Electric Potential
A 3.0 μc charge is moved through a potential difference of 640 V. What is its potential energy change? How much work would be done BY THE ELECTRIC FIELD in moving a 2 mc charge from A to C? From A to B? from B to C?. How much work would be done my an external force in each case? y(m) C A B Electrical Potential in Uniform Electric Fields x(m) An electric field is parallel to the x-axis. What is its magnitude and direction if the potential difference between x = m and x = 2.5 m is found to be +900 V? Conservation of Energy You know what Conservation of Energy is. We just need to work some problems. If a proton is accelerated through a potential difference of 00 V, what is its change in potential energy? What is the voltmeter reading between A and B? Between A and C? Assume that the electric field has a magnitude of 400 N/m. y(m) C How fast will this proton be moving if it started at rest? A B x(m) AP Physics 2 Chapter 16: Electric Potential
A proton at rest is released in a uniform electric field. What potential difference must it move through in order to acquire a speed of 0.20 c? How much work was done in assembling the charge configuration shown below? -3 μc 2 μc 4 μc Electric Potential Energy of Spherical Charges Electric Potential (spherical) Formula: What is the potential energy of the configuration shown below? What is the electric potential at (2,2)? -3 μc 2 μc 4 μc 2 μc 4 μc Equipotential surfaces: parallel plate capacitor AP Physics 3 Chapter 16: Electric Potential
Equipotential surfaces: positive point charge Draw a negative point charge of -Q and its associated electric field. Draw 4 equipotential surfaces such that ΔV is the same between the surfaces, and draw them at the correct relative locations. What do you observe about the spacing between the equipotential surfaces? Equipotential surfaces: negative point charge Question What can you say about the intersection between field lines and equipotential surfaces? Fill in the following table for spherical charges Force Potential Energy Field Potential Draw field lines for the charge configuration below. The field is 600 V/m, and the plates are 2 m apart. Label each plate with its proper potential, and draw and label 3 equipotential surfaces between the plates. You may ignore edge effects. - - - - - -- - -- - -- - -- - -- - - - - - - - - - - - - - - - - - + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + AP Physics 4 Chapter 16: Electric Potential
Capacitance Define Capacitance in words Combining Capacitors How do Capacitors combine when in parallel? Write a general equation to describe this. Define Capacitance in an Equation in terms of other electric variables. How do capacitors combine in series? Define Capacitance physically for a parallel plate capacitor in an equation. Write a general equation to describe this. Two plates separated by 0.02 m need a charge on them of 9 x 10-5 C when a voltage of 15 V is applied. (a) What area plates should be used? Reduce the following to one Equivalent Capacitance. (b) How much energy would be stored in this setup? AP Physics 5 Chapter 16: Electric Potential