
Each bulb is connected to the same potential difference, that of the battery, so they all have _____ ______ brightness.
In the second circuit, the battery must power two light bulbs, so it provides twice as much _______
 the same
 current

50 and 100 ohms are in series and the 75 ohm resistor is parallel so A.

 The second is parallel so it uses more current, however, the brightness is equal.
 E.) A = B = C

A. the light bulb connected to 110V has 60 W and 100 W respectively. Thus, 60W has a higher resistance than 100W from P = V^{2}/R
Next, they are now connected in series, so same amount of current pass through both bulbs. The one with higher resistance will dissipate more power (P = I^{2}R). Thus, the 60 W bulb will dissipate more power than the other one. So, should be brighter.

B. V^{2}/R because its in a parallel configuration, the resistors have the same potential.

 Ohm's Law:
 I = V/R_{eq} = V/(R_{1} + R_{2} +R_{3})
 1.0 = 9/(3 + 2.5 + R_{3})
 1.0 = 9/(5.5 + R_{3})
 5.5 + R_{3} = 9
 R_{3} = 9  5.5
 R_{3} = 3.5 Ω

 Calculations for left circuit:
 R_{eq}= 36 Ω
 Current through circuit:
 I= V/R= 9/36= 0.25 A
Power: P= I ^{2}R= 0.25*0.25* 36= 2.25 W
 Calculations for right circuit:
 R_{eq} = 18*18/(18+18)= 9 Ω
 Current through circuit:
 I = V/R= 9/9= 1 A
 Power:
 P= I^{2}R = 1*1* 9= 9 W
Power of right circuit is more than power of left circuit.

A circuit consisting of resistors can often be reduced to a simple circuit containing only one resistor. State the 4step process

If the current in or the potential across a resistor in the initial circuit is to be found, start with the ______ ______ and gradually work your way back through the ______ ______.
Find currents and voltages across resistors using ΔV = ____ and your understanding of ______ and ______ _______
 final circuit
 equivalent circuits
 ΔV = IR
 series and parallel combinations

Household circuits are always wired so that the electrical devices are connected in _______.
☞Each device operates _______ of the others so that if one is switched off, the other remains on
☞Each device operates on the same _______
 parallel
 independently
 voltage

If devices were connected in _____, the voltage applied to the combination would divide among the devices
The _______ applied to any one device would depend on how many devices were in combination

1. Safety fuses
☑ Wires melt when current is ________
☑ Connected in _______ along supply line to prevent overloading
☑ Commonly replaced by ______ ______
2. Circuit breaker
☑ Circuit breakers are used in ______ with other circuit elements for safety purposes
☑ A circuit breaker is designed to switch off and open the circuit at some _______ ______
☑ If a circuit breaker were not used, large currents caused by ______ _____ many devices could result in excessive ________ in wires and perhaps, cause a fire
 excessive
 series
 circuit breakers
 series
 maximum current
 turning on
 temperatures

Device that measures the current in a circuit element is a(n) ________. An ammeter must be placed _____ ______ with the circuit element whose current is to be measured.
The ammeter's resistance must be much less than R in order for it to not change the ______ of the circuit
The resistance of an ideal ammeter is _____ so that it can measure the current without _______ the current
What happens if you accidentally connect the ammeter in parallel?
 ammeter
 in series
 current
 zero
 changing
 device will short circuit

A device that measures the potential difference across a circuit element is a _______.
A voltmeter must be placed in ______ with the circuit element whose _______ _______ is to be measured.
The voltmeter's resistance must be much _______ than R in order not to affect the circuit
An ideal voltmeter has _______ resistance so that it can measure the voltage without _______ the voltage
 voltmeter
 parallel
 potential difference
 larger
 infinite
 changing
 **Note: 1/R_{eq} = 1/R_{1} + 1/R_{voltmeter (very big/close to infinity)}
 R_{eq} must be close to R1
 R_{eq} < R_{1 }+ R_{voltmeter}


E. Because this in parallel, it'll fry the meter

Combinations of resistors can often be reduced to a single equivalent resistance through a stepbystep application of the ______ and _______ rules
State the Two special cases:
 series and parallel rules

Detail Problem Solving approach for Circuit Problems

Detail Problem Solving strategy for Kirchhoff's Rules

Additionally, the ε = 9.0 V, find the current through R _{3}
check notes


