AP PHYSICS
Ohm’s Laws, Kirchoff’s Laws
pg 1
Kirchoff’s Laws Objectives
Students will be able to :
1. From memory know
• V=IR as Ohm’s Law
• Define Kirchoff’s junction rule
• Define Kirchoff’s Loop rule
2. Find the total resistance of a simple dc circuit of resistors (1 battery = simple)
3. Reconize a “loop” in a circuit.
4. Apply Kirchoff’s rules to
5. Find the current in a single loop circuit with more than one battery.
6. Find the unknown voltage or resistance in single loop circuit with more than one battery
7. Divide up a complex circuit into loops
8. Use the loop and juntion rules to calculate the currents in each loop (or branch) of a circuit.
9. Use the graphing calculator’s matrices functions to find any unknowns ina system of equations
(usually for multiple currents in a circuit.)
10. Use Kirchoff’s loop rule to calculate the potential difference between any two points in a circuit.
AP PHYSICS
(1)
Ohm’s Laws, Kirchoff’s Laws
pg 2
Which direction is the current flowing? Clockwise or Counter- Clockwise
1V
1/2 Ω
1Ω
a
b
8V
1V
2Ω
1/2 Ω
d
c
4V
(2)
I=?
V ab =
V cd =
V db =
P8v =
P2Ω =
4V
2V
AP PHYSICS
Ohm’s Laws, Kirchoff’s Laws
pg 3
For the circuit below, calculate:
(3) The direction of each current in the top circuit loop.
(4) The direction of each current in the bottom circuit loop.
(5) The current through each resistor.
(6) The total resistance of the circuit.
(7) The power dissipated by each resistor and battery
4Ω
24 v
8Ω
8Ω
AP PHYSICS
Ohm’s Laws, Kirchoff’s Laws
pg 4
For the circuit below, calculate:
(8) The direction of each current in the top circuit loop.
(9) The direction of each current in the bottom circuit loop.
(10) The current through each resistor.
(11) The total resistance of the circuit.
(12) The power dissipated by each resistor and battery
24 v
4Ω
8Ω
8v
8Ω
AP PHYSICS
Ohm’s Laws, Kirchoff’s Laws
pg 5
For the circuit below, calculate:
(13) The direction of each current in the top circuit loop.
(14) The direction of each current in the bottom circuit loop .
(15) The current through each resistor.
(16) The total resistance of the circuit.
(17) The power dissipated by each resistor and battery
24 v
4Ω
8Ω
4v
4v
4Ω
4Ω
AP PHYSICS
Ohm’s Laws, Kirchoff’s Laws
pg 6
For the circuit below, calculate:
(18) The direction of each current in the left circuit loop.
(19) The direction of each current in the right circuit loop.
(20) The current through each resistor.
(21) The total resistance of the circuit.
(22) The power dissipated by each resistor and battery
24 v
8Ω
8Ω
4Ω
4Ω
12v
4Ω
4v
AP PHYSICS
Ohm’s Laws, Kirchoff’s Laws
pg 7
For the circuit below, calculate:
(23) The direction of each current in the left circuit loop.
(24) The direction of each current in the right circuit loop.
(25) The current through each resistor.
(26) The power dissipated by each resistor and battery
3v
2Ω
6v
3Ω
9v
12 v
4Ω
4Ω
2Ω
1.5 v
6Ω
AP PHYSICS
Ohm’s Laws, Kirchoff’s Laws
pg 8
For the circuit below, calculate:
(27) The direction of each current in the left circuit loop.
(28) The direction of each current in the right circuit loop.
(29) The current through each resistor.
(30) The power dissipated by each resistor and battery
3v
2Ω
15 v
3Ω
6v
12 v
4Ω
9v
6Ω
3v
12 v
5Ω