Download Unit 7: Electrical Circuits and Systems Review KEY

8.
If resistance is decreased in a circuit, what happens to the current? What law is this?
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9.
The current increases when resistance decreases. Ohm’s Law states V = IR.
A motor in a toy car needs 1.2 amps of current to work properly. If the car runs on four
1.5-volt batteries, what is the motor’s resistance?
6
10.
What is the voltage in a radio with 5 Ω resistance and 8
(8 )( 5 Ω)
11.
Multiple devices can run at full power.
Turning off one device does not affect all devices.
What is the same for all points in a series circuit? In a parallel circuit?
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13.
120 V
What are two advantages of parallel circuits compared to series circuits?
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12.
of current?
Current is the same for all points on a series circuit
Voltage is the same for all points in a parallel circuit
series circuit contains a
6Ω
a. Draw the circuit.
battery and three bulbs with resistances of
Ω, 4 Ω, and
b. What is the total resistance of the circuit?
RT = R1 +R2 + R3
Ω +4Ω +6Ω
12 Ω
c. What is the current in the circuit?
Ω
14.
A series circuit contains a 12 volt battery and two identical bulbs for 2 A of current. What
is the voltage drop across each bulb?
Voltage drop = 12 V/ 2 bulbs = 6 V