AP Physics
Monday 14.03.16
Standards: B2Capcitors A relate
stored charge, voltage, and
stored energy for a capacitor
Objective: SWBAT understand
what a capacitor is made of
and understand how capacitors
store charge for later use.
Agenda
1. Warm Up
2. Review HW
3. Capacitors Notes
4. Capacitors Practice.
Warm Up
If a charged object moves in an
electrical potential field from 60 V to -30 V. Is work being
done by the electric field or by
an applied force? Find the
work done if the charge was
1.6μC.
Homework
C#12
AP Physics
Tuesday 14.03.17
Standards: Identify parallel and
series circuits & calculate their
equivalent resistance.
Objective: SWBAT solve
problems involving multiple
resistors
Warm Up
NO CLASS
Agenda
1. Warm Up
Homework
AP Physics
Wednesday 14.03.18
Standards:
C2 a,b, students should understand
current, resistivity, and the relationship
between current and voltage.
Objective: SWBAT solve problems
involving simple circuits.
Agenda
1. Warm Up
2. Review HW
3. Circuits
Warm Up
Find the capacitance of a
parallel plate capacitor with an
Area of 10 cm2 and an plate
separation distance of 0.6 m.
Homework
C#13
AP Physics
Thursday 14.03.19
Warm Up
Find the current of an electric circuit with a
resistance of 10Ω and 5V? Draw a circuit
diagram.
Standards: Identify parallel and series
circuits & calculate their equivalent
resistance.
Objective: SWBAT solve problems
involving multiple resistors
Agenda
1. Warm Up
2. Review HW
3. Pass out Permission Slip Forms
Homework
C#14
AP Physics
Friday 14.03.20
Standards: Power, Series &
Parallel Combined Circuits
Objective: SWBAT find the
power used in electric circuits
Warm Up
Req=?
10Ω
12Ω
20V
6Ω
I=?
Vdrop across each resistor=?
Agenda
1. Warm Up
2. Review HW
3. Series & Parallel Mixed Circuits
4. Power in Electric Circuits.
5. E#15
Homework
E#15
8Ω
Capacitance Guided Practice
Consider a parallel-plate capacitor the size of Nauru, an island
with an area of just 21 km2. If 100 V is applied across the
capacitor to store 55J of electrical potential energy, what is the
capacitance of this capacitor? If the area of its plates is the
same as the area of Nauru, what is the plate separation?
d=2 cm
Capacitance: Fahrrads (Coulomb/Volt) –
Stored charge per volt.
Uc=(1/2) QV, Q2/2C, (½)CV2
C=εoA/d
Q=CV
C#12 Capacitance HW
a. C=?
Q= 1μC
V=10 V
1.
2.
3.
b Q=?
C=10C/V
E=10N/C
D=2m
c.
C=?
A=12m2
d=20m
ε0=8.85x1012C2/(Nm2)
d. Q=?
A=1m2
d=10cm
V=5V
e. Find U
for a,b,&d.
To improve the short-range acceleration of an electric car, a capacitor may be
used. Charge is stored on the capacitor’s surface between a porous
composite electrode and electrolytic fluid. Such a capacitor an provide a
potential difference of nearly 3.00x102V. If the energy stored in this capacitor
is 17.1 kJ, what is the capacitance?
Air becomes a conductor if the electric field across it exceeds 3.0x106V/m.
What is the maximum charge that can be accumulated on an air-flled
capcaitor with a 0.2 mm plate separation and a plate area equal to the area of
the worlds largest painting (6.7x103m2)
The largest lasagna in the world was made in California in 1993. It had an area
of approximately 44 m2. Imagine a parallel-plate capacitor with this area that
is filled with air. If a potential difference of 30.0 V is placed across the
capacitor, the stored charge is 2.5μC.
a. Calculate the capacitance of the capacitor
b. Calculate the distance that the plates are separated.
c. Calculate the electrical potential energy that is stored in the capacitor.
1985B3. An electron initially moves in a horizontal direction and
has a kinetic energy of 2.0 x 103 electron–volts when it is in the
position shown above. It passes through a uniform electric field
between two oppositely charged horizontal plates (region I) and
a field–free region (region II) before eventually striking a screen
at a distance of 0.08 meter from the edge of the plates. The
plates are 0.04 meter long and are separated from each other
by a distance of 0.02 meter. The potential difference
across the plates is 250 volts. Gravity is negligible.
a. Calculate the initial speed of the electron as it enters region I.
b. Calculate the magnitude of the electric field E between the plates, and indicate its
direction on the diagram above.
c. Calculate the magnitude of the electric force F acting on the electron while it is in
region I.
d. On the diagram below, sketch the path of the electron in regions I and II. For each
region describe the shape of the path.
C#13 Circuit Basics
1.
2.
3.
4.
5.
Draw the symbol for resistor.
Draw the symbol for current.
Draw the symbol for voltage.
Draw a simple circuit with 1 resistor.
If 3x104C of charge flows across a point in a wire in 500 s, what is
the current passing through that point in the wire?
6. If the electric current flowing through a wire is 4 A, how long will it
take for 1μC to flow through the wire?
7. Find the amount of resistance in a circuit that turns on a light bulb
if a 9 V battery pushes or drives the 0.33 Amp current.
8. Find the voltage that drives a 10 A current traveling through a wire
if the resistance of 20Ω.
9. What is the resistance of a cupper wire with a radius of 0.5 cm
and a length of 2000 m when the resistivity is ρal=1.70x10-8m?
10. Find the resistivity of an unknown metal wire with a radius of 20
cm and a length of 4 meters which produces a resistance of 1 Ω
E #14 Series & Parallel Circuits
For each: Find Req, then find the unknown currents and voltages.
2.
1.
4Ω
2Ω
4Ω
2Ω
3A
10V
6Ω
V
6Ω
3.
I
2Ω
I2
4Ω
I
I3
4Ω
4Ω
2Ω
C
I1
I
4.
24V
24V
I1
I2
E#15 Electric Circuits FRQ
1976B3. In the circuit shown above, the current
delivered by the 9-volt battery of internal resistance 1
ohm is 3 amperes. The power dissipated in R2
a. Determine the reading of voltmeter V in the
diagram is 12 watts.
b. Determine the resistance of R2
c. Determine the resistance of R1
1986B3. In the circuit shown above, X, Y. and Z represent three
light bulbs, each rated at 60 watts, 120 volts. Assume that the
resistances of the bulbs are constant and do not depend on the
current.
a. What is the resistance of each bulb?
b. What is the equivalent resistance of the three light bulbs
when arranged as shown?
c. What is the total power dissipation of this combination when
connected to a 120-volt source as shown?
d. What is the current in bulb X?
e. What is the potential difference across bulb X?
f. What is the potential difference across bulb Z ?