Download Review Powerpoint (including Ex Problem Answers)

Plan for Today (AP Physics I)
• Go over review problems
• Go over complex circuits worksheet
• In-class review
Calculate the potential difference at a
point in space
• Due to one or more point charges
– V = kq/r
– Then you can add them up if you have multiple
charges (remember, voltage is scalar, but may
have signs)
• In a uniform electric field
– V = Ed, V = PE/q
Calculate the electric potential energy
• Due to one or more point charges
– PE = -kq1q2/r2
• In a uniform electric field
– PE = -qEd
– Think about what signs mean
– Also be able to relate to other energies (like KE)
Parallel Plate Capacitors
• Their basic structure
• What a dielectric does
• Equation C = q/V
Types of Problem
• Calculate the capacitance given area and
distance
• Calculate the capacitance given the charge
and voltage
• Calculate with a dielectric constant
Capacitors in series and parallel
circuits
Series
• Q’s are all equal
• Vs add
Parallel
• Vs are all equal
• Qs add
Parallel vs. Series
• Which would have the greatest equivalent
capacitance?
• Parallel
• Why?
• Least?
• Series
• Why?
• Complex circuits (series and parallel)
Types of Problems
• Complex circuits – calculate equivalent
capacitance
• Complex circuits – calculate qs and vs on each
capacitor
• In series and parallel, calculate vs and qs on
each capacitor
Dielectric constant
• Know how a dielectric works
• Know how to apply these to the capacitance
equation
• What it does for capacitance
Types of problems
• Calculate capacitance given a k
• Explain how dielectrics work
Energy stored in a capacitor
Types of Problem
• Find the potential energy of a system given 2
of the following: charge, capacitance, or
voltage
Example 1
• A 5 uC charge is .6 m away from a 8 uC charge.
Find the potential difference at a point
halfway between them.
Example 2
• An electron is moved between two parallel
plates with an electric field of strength 300
N/C a distance of 2 mm.
– What is the potential difference between the
plates?
– What is the potential energy of the charge?
– What is the velocity of the electron when it is
moved from the negative plate to the positive
plate?
Example 3
• A capacitor has an area of 15 square
centimeters. The plates are separated by .5
mm. What is its capacitance?
• What would the capacitance be if water was
plates between the plates (dielectric constant
of 80)?
Example 4
• Calculate the equivalent capacitance for the
following circuit
Example 5
• Calculate the charge and voltage on each
capacitor in the following circuit
Example 1
• A 5 uC charge is .6 m away from a 8 uC charge.
Find the potential difference at a point
halfway between them.
Example 2
• An electron is moved between two parallel
plates with an electric field of strength 300
N/C a distance of 2 mm.
– What is the potential difference between the
plates?
– What is the potential energy of the charge?
– What is the velocity of the electron when it is
moved from the negative plate to the positive
plate?
Example 3
• A capacitor has an area of 15 square
centimeters. The plates are separated by .5
mm. What is its capacitance?
• What would the capacitance be if water was
plates between the plates (dielectric constant
of 80)?
Example 4
• Calculate the equivalent capacitance for the
following circuit
Example 5
• Calculate the charge and voltage on each
capacitor in the following circuit