1. AP Physics Monday 14.03.24 Homework Electricity Test Thursday E#16 Warm Up Agenda 1.Warm Up 2.Collect Homework 3 weeks 3.Review Homework 4.Kirchoff’s Laws 5.E#16 Standards: 2b Students should be able to apply Ohm’s Law and Kirchoffs rules to direction current circuits. Objective: SWBAT use Kirchoff’s Laws to describe complex circuits V 2A 12Ω36Ω Find V, I 1, and I 2

2. Agenda 1.Warm Up 2.WU Answer: I 2 =(1/9)A, I 3 =(-1/3)A I 1 =(-2/9)A 3.FRQ Problem Warm Up Homework E#17 FRQ Problem AP Physics Tuesday 14.03.25 Standards: 2b Students should be able to apply Ohm’s Law and Kirchoffs rules to direction current circuits. Objective: SWBAT use Kirchoff’s Laws to describe complex circuits 4v 12Ω 36Ω Find I 1 I 2, I 3 8V

3. AP Physics Wednesday 14.03.26 Agenda 1.Warm Up 2.Review HW 3.RC Circuits Homework E#17 Warm Up Standards: 2b Students should be able to apply Ohm’s Law and Kirchoffs rules to direction current circuits. Objective: SWBAT solve problems involving charged capacitors. 10v 18Ω 12Ω Find I 1 I 2, I 3 5V

4. AP Physics Thursday 14.03.27 Homework RC Circuits E#18 Warm Up Standards: 2b Students should be able to apply Ohm’s Law and Kirchoffs rules to direction current circuits. Objective: SWBAT solve problems involving charged capacitors. Agenda 1.Warm Up 2.Review HW 3.RC Circuits 6v 4Ω 12Ω Find I 1 I 2, I 3 3V 8Ω

5. AP Physics Friday 14.03.28 Homework Study for Test E#19 Post 1 Question on the Forum in preparation for the test 10 pts Warm Up Agenda 1.Warm Up 2.Test Review 3.Test Information Standards: Electrostatics & Electric Circuits. Objective: SWBAT compete in a review session to win extra credit. 10v 10μF Find the equivalent capacitance and the total charge stored in this circuit.

6. Kirchoff’s Rules 1.A point where three or more wires are joined is called a junction or node. 2.A path connecting two junctions is called a branch. A branch may contain one or more circuit elements and there may be more than two branches between two junctions. 3.ΣI=0 (Currents entering a junction are positive and currents exiting a junction are negative) Current in = Current out 4.ΣV=0 (Conservation of Energy)

7. Applying Kirchoff’s Rules p.601 1.Assign a current and direction of current for each branch in the circuit. 2.Identify the current loops and their directions. 3.Apply Kirchoff’s Rule for each loop to give you a unique set of equations. ΣI=0 4.Apply the loop theorem ΣV=0 using V=IR

8. Kirchoff’s Rules Simple Demo 1. How many nodes or junctions are there? Identify them on your diagram 2.How many branches are there? Identify them on your diagram. 3.Find the current traveling through Junctions 1,2,&3 using Kirchoff’s law. 8V I 1,I 2,I 3 =? 2Ω 2.

9. Guided Practice Kirchoff’s Rules 1V I1I1 1Ω 1V I2I2 I3I3 1Ω 1. How many nodes or junctions are there? Identify them on your diagram 2.How many branches are there? Identify them on your diagram. 3.Find the current traveling through Junctions 1,2,&3 using Kirchoff’s law. 1Ω

10. Kirchoff’s Laws E#16 V 4Ω 8Ω 8V I 1,I 2,I 3 =? 8Ω 2A 4Ω 1. 2. Solve using Kirchoff’s rules 4V 5Ω 10Ω 3. 15Ω 4V 12V 4V 6V 14Ω 6Ω 8Ω Find the magnitude and direction of the currents (I 1,I 2,I 3 ) for the following two problems. 4. 8Ω

11. Kirchoff’s Laws Extension E#17 1981B4. A circuit consists of battery A of emf EA = 60 volts and internal resistance rA = 3 ohms; battery B of emf EB = 12 volts and internal resistance rB = 1 ohm; and four resistors connected as shown in the diagram above. a. Calculate the current in the 2-ohm resistor. b. Calculate the power dissipated in the 3-ohm resistor. c. Calculate the terminal voltage of battery Another symbol for voltage source A symbol for a larger voltage source like a battery.

12. RC Circuits#E18 9V I 2. 8μF 6μF 9V I 8μF 6μF 1. For each circuit find the total capacitance & find the charge stores on each capactor. 9V I 20μF 10μF 3. This is an RC Circuit. When the switch is open what is the current going through the resistor? When you close the switch, the capacitors charge. How much charge and energy will be stored in each capacitor? 4Ω

13. RC Circuits All we need to know for RC circuits are generally how they work, and how to calculate their initial conditions. These circuits are time dependent, so they require calculus. -In these circuits, the current varies over time. The max current is I 0 =V 0 /R, Q 0 =CV 0 - These values are valid initially right when the circuit is connected, but over time as charge is deposited onto the capacitor, the voltage and the current will decrease until the capacitor stops charging completely. Once the capacitor stops charging there is no more current or voltage. The circuit comes to a halt. That is until the capacitor discharges its stored charge and releases its energy. -Charging and discharging of a capacitor proceeds at an exponential rate.

14. 1985B3. An electron initially moves in a horizontal direction and has a kinetic energy of 2.0 x 10 3 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. E#19 Test Review FRQ

15. Kirchoff & RC Extra Credit 12V Find the C eq and the charge across each capacitor when fully charged. #2 only: Find the current (I) and the R eq after the capacitors have fully charged. 3μF 20V I 5μF 15μF 4Ω 8Ω 3μF 2. 5Ω 10V 5Ω 4. 5Ω 5V 5Ω 4V 4Ω 2Ω 2V 3. 6Ω 1. Use Kirchoff’s Law to find I 1,I 2 & I 3. Answers to be posted Sunday March 30th