Name: 
 

Unit 9 PREP-TEST: Electricity & Magnetism


Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1 
The amount of charge that moves through the filament of a lightbulb in 2.00 s is 2.67 C. What is the current in the lightbulb?
A
5.34 A
C
0.835 A
B
1.33 A
D
0.417 A
 

 2 
In this circuit, what is the current through the 6.0-ohm resistor?
mc002-1.jpg
A
0.2 A
C
5.0 A
B
1.7 A
D
8.0 A
 

 3 
mc003-1.jpg
In the circuit shown above, the meter registers 5-amperes. The voltage across the 5-ohm resistor is about
A
5 C
C
25 V
B
20 V
D
30 V
 

 4 
A 12-V battery is connected to a light bulb with a resistance of 0.50 mc004-1.jpg. What is the current in the circuit?
A
24 A
C
1.0 A
B
3.0 A
D
0.3 A
 

 5 
An electric appliance draws 2.2 amperes of current when it is connected to a 24-volt source. What is the resistance of this appliance?
A
0.063 ohm
C
16 ohms
B
11 ohms
D
54 ohms
 

 6 
mc006-1.jpg
What is the current through the battery?
A
1 A
C
4 A
B
2 A
D
8 A
 

 7 
mc007-1.jpg
How much power is dissipated by the resistor in the circuit above?
A
25 watts
B
50 watts
C
100 watts
D
800 watts
 

 8 
Which of the following affects a material’s resistance?
A
the length of the material
C
the temperature of the material
B
the type of material
D
All of the above
 

 9 
Which of the following wires would have the least resistance?
A
an aluminum wire 10 cm in length and 3 cm in diameter
B
an aluminum wire 5 cm in length and 3 cm in diameter
C
an aluminum wire 10 cm in length and 5 cm in diameter
D
an aluminum wire 5 cm in length and 5 cm in diameter
 

 10 
If a mc010-1.jpg W lightbulb operates at a voltage of 120 V, what is the current in the bulb?
A
0.62 A
C
1.95 ´ 10mc010-3.jpg A
B
1.6 A
D
9.0 ´ 10mc010-4.jpg A
 

 11 
Doubling the current in a circuit with constant resistance has the effect of changing the power by what factor?
A
mc011-1.jpg
C
4
B
mc011-2.jpg
D
9
 

 12 
If the current through a 250 W heater is 0.50 A, what is the potential difference across the ends of the heating element?
A
1.25 ´ 102 V
C
2.50 ´ 10mc012-3.jpg V
B
5.0 ´ 10mc012-2.jpg V
D
1.3 ´ 102 V
 

 13 
If a 1950 W heater has a current of 6.0 A, what is the resistance of the heating element?
A
88 W
C
9.0 W
B
54 W
D
4.5 W
 

 14 
An electric toaster requires 3700 W at 110 V. What is the resistance of the heating coil?
A
3.3 W
C
10 W
B
9.0 W
D
11 W
 

 15 
Three 2.0 W resistors are connected in series. What is their equivalent resistance?
A
18 W
C
6.0 W
B
8.0 W
D
1.8 W
 

 16 
In a series circuit, which of the following best describes the current in the circuit?
A
It = I1 + I2 + I3
C
It = I1 = I2 = I3
B
It = mc016-1.jpg
D
It = mc016-2.jpg
 

 17 
If the resistance of each resistor is known in a series circuit, how would you determine the equivalent resistance of the circuit?
A
the sum of all resistors
C
all resistors must have the same restistance
B
the reciprocal sum of all resistors
D
not enough information is available to answer this question
 

 18 
If the potential difference in each resistor of a parallel circuit are known, how would you best determine the circuit’s overall potential difference?
A
DVt = DV1 + DV2 + DV3
C
DVt = DV1 = DV2 = DV3
B
DVt = mc018-1.jpg
D
DVt = mc018-2.jpg
 

 19 
Three 2.0 W resistors are connected in parallel. What is their equivalent resistance?
A
20.0 W
C
0.67 W
B
12 W
D
6.0 W
 

 20 
When direct current flows through a straight segment of wire, the magnetic field produced
A
circles around the wire
C
runs parallel to the wire
B
runs perpendicular to the wire
D
does not exist
 

 21 
mc021-1.jpg
A coil with a current is shown above. In the center of the coil, a magnetic field points
A
to the right.
C
upward.
B
to the left.
D
downward.
 

 22 
Magnetism is a result of
A
magnetic monopoles.
C
the alignment of charged particles.
B
hidden voltage.
D
random current.
 

 23 
As electric current travels through a wire and encounters resistance, some of the electrical energy is
A
lost.
C
converted to power.
B
converted to heat.
D
converted to electrical potential energy.
 

 24 
The graph below shows the I-V characteristic of a particular electrical component.
mc024-1.jpg
What physical quantity does the slope represent?
A
Resistance
C
Power
B
Potential Difference
D
Current
 

 25 
The graphs below are the current-voltage (I-V) characteristics of three electrical components P, Q and R.
mc025-1.jpg
Which component(s) is ohmic?
A
P only
C
P and Q only
B
R only
D
P and R only
 



 
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