Download Review Test #6: Electric Circuits

Electric Circuits Test Review
Reading: Ch. 22 p.p. 590-609, Ch. 23 p.p. 616-635
Topics: Basic Circuit, Current, Voltage, Ohm’s Law & Resistance, Diagramming Circuits, Electric
Energy & Power, Series & Parallel Circuits, Electrical Safety
Labs & Activities: Connecting Bulbs to Batteries, Resistors Lab, Series & Parallel with Bulbs,
Resistors in Series & Parallel
V= W
q
I=q
t
I= V
R
P = IV
P=W
t
Req = R1 + R2
1 = 1 +1
R eq R1 R2
Objectives:
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Be able to explain what is necessary for charge to flow continuously.
Know the parts of a battery and how a battery functions in a circuit.
Know voltage or electric potential difference (V) is the electric potential energy per charge
and that a battery gives charge a voltage while voltage is lost when a charge passes through
an electronic component like a bulb or resistor.
Know why a light bulb lights immediately when connected in a circuit.
Know current (I) is the rate of charge flow measured in Amps (A) and be able to calculate it.
Be able to diagram and explain the role of an ammeter and a voltmeter.
Know resistance (R) restricts the flow of current and is measured in ohms (Ω).
Understand the relationship between V, I & R – Ohm’s Law.
Be able to use the relationship between electric power, voltage and current.
Know the relationship between the electrical energy transformed by an appliance and the
appliance’s power rating and be able to calculate the cost to use an appliance.
Know how wiring in series and parallel affects resistance and current of a circuit.
Know how to do calculations for resistors in series and parallel.
Be able to analyze complex resistor circuits.
Know how a fuse and circuit breaker work.
Know what a short circuit is.
Practice:
1.
How should you connect four bulbs to a battery so 2 are bright and 2 are dim? Draw a
diagram of the circuit.
2. Valerie’s 180 W electric rollers are plugged into a 120 V line in her bedroom.
a. What current do the curlers draw?
b. What is the resistance of the rollers?
3. A circuit in your home has a 15 A circuit breaker. How many 60 W incandescent bulbs can
be operated at the same time using 120 V?
4. Not enough heat from the furnace reaches one bedroom in a home. Therefore the
homeowner uses a portable 1350 W heater 8 hours per day during the four coldest months
of the year. At $0.14 per kilowatt-hour, how much does it cost to operate the heater for
all four months? (Assume two months are 31 days while the other two are 30 days.)
5. For the series circuit shown, calculate the voltage across the 4 Ω resistor.
4Ω
8Ω
36 V
6. For the parallel circuit shown, calculate the total current from the battery and the current
through the 10 Ω resistor.
120 V
10 Ω
15 Ω
7. What is the total current of the circuit shown?
6Ω
2Ω
12 Ω
5Ω
24 V
8. Answer the following questions. Your choices are “go up”, “go down” or “stay the same.”
a.
If a resistor is added in series, the total resistance will __________.
b. If a resistor is added in series, the total current will __________.
c.
If a resistor is added in parallel, the total resistance will __________.
d. If a resistor is added in parallel, total current will __________.
9. Predict the relative brightness of each bulb in the circuit shown. Explain what would happen
to the other bulbs if bulb A burns out. Where should a switch be placed to make all the
bulbs turn on and off together?
D
10. The current through a light bulb is 0.835 A. If the bulb is plugged into a 120 V outlet, how
much electrical energy does it transform in 2 minutes?