Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
Aload resistor has 12 Vacross it and 20 mA through it. Aresistor is added in series and the current
drops to 10 mA. The value of the second resistor is
1)
A)
50
B)
75
C)
300
D)
600
2)
The parallel combination of 1 kand 2 kresistors are in series with a 3 kresistor. The total
resistance is
2)
A)
667
B)
3.67 k
C)
6 k
D)
545
B
3)
There are two resistors connected in series with 22 Vacross them. You can read the color code on
one of them fired–red–orange–gold). That resistor has16 Vacross it. The value of the other resistor is
3)
A)
9.1 k
B)
8.2 kW
C)
8.5 k
D)
8 k
B
4)
There are 3resistors in series with a36 Vsource. The voltage across the first resistor is 8V. The
power dissipated by the second resistor is 100mW. The current through the third resistor is 8mA.
The resistances of the three resistors are
4)
A)
1 k,1.4 k, 2 k
B)
1 k,1.6 k, 2 k
C)
2 k,1.6 k, 2 k
D)
1 k,1.4 k,1.8 k
B
5)
1 k,1.2 k,and 2.2 kresistors are connected in series. The total resistance is
5)
A)
3.4 k
B)
4.4 k
C)
4.2 k
D)
909
B
1
D
6)
A12 Vsupply is connected to aseries pair of 1 kresistors. Subsequently, a 3 kresistor is added
in series. The percentage change in total current is
6)
A)
30 %
B)
120%
C)
60 %
D)
–60 %
7)
2.2 k,4.7 k,and 6.8 kresistors are connected in parallel. The current through the 6.8 kresistor
is 3.4 mA. The total current is
7)
A)
15.4 mA
B)
1.23 mA
C)
18.8 mA
D)
23.12 mA
C
8)
A10 kand a100kresistor are connected in parallel. A4.7 kresistor is added in series. If the
current through the 10 kresistor is 1mA, the source voltage is
8)
A)
12.4 V
B)
15.2 V
C)
10.5 V
D)
Not enough information to determine
B
9)
You measure 3mA through a 1 kresistor that is in series with a1.2 kand a6.8 kresistor. The
source voltage is
9)
A)
3 V
B)
27 V
C)
24 V
D)
Not enough information to determine
B
10)
The current through a100 resistor is 5.3 mA when in parallel with a47 resistor. The total
current is
10)
A)
1.66 mA
B)
54.1 mA
C)
11.3 mA
D)
16.6 mA
D
2
D
11)
A100mA current source with aparallel 50 source resistance is connected to a50 load. The
power in the load is
11)
A)
125mW
B)
30 mW
C)
250mW
D)
500mW
12)
An 18 Vsource has a50 source resistance. The load resistance is set to match the source
resistance. The power dissipated in the load is
12)
A)
2 W
B)
1.6 W
C)
3.2 W
D)
180mW
B
13)
2 k, 3 kand 4 kresistors are connected in parallel. The total resistance is
13)
A)
0.923
B)
9 k
C)
2 k
D)
923
D
14)
The voltage across a100resistor is 1.75 Vwhen connected in series with a 5 V source and an
unknown resistance. The unknown resistance value is
14)
A)
86
B)
289
C)
285
D)
186
D
15)
There are three resistors in parallel with a24 Vsupply. The current through the first resistor is 12
mA. The power dissipated by the second resistor is 120mW. The third resistor is equal to the
parallel combination of the first two. The resistances of the three resistors are
15)
A)
2 k,4.8 k,1.4 k
B)
2 k,68 k, 1 k
C)
2 k,69 k,1.8 k
D)
2 k,69 k,10 k
A
3
A
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
16)
Determine Vab for Figure 3–1. Vab = ________
16)
17)
Apractical voltage source of 100Vwith asource resistance of 50 is equivalent to acurrent
source of ________ and aparallel resistance of ________.
17)
18)
Resistors of 2.2 k,3.3 k,and 4.7 kare connected in series. The supply is 12 V. The
voltages across the individual resistors are ________, ________, and ________.
18)
19)
If the voltage across R1is 10 Vand R2is 15 Vand R3is 20 V, and if the resistors are in
series, the supply voltage is ________. You would use ________ to find this.
19)
20)
Apractical current source of 4 A with a100resistance is equivalent to a voltage source of
________ and asource resistance of ________.
20)
21)
The total resistance for six 100Wlight bulbs on a120Vhouse circuit (connected in parallel)
is ________.
21)
4
22)
Determine Vab for Figure 3–2. Vab = ________
22)
23)
Resistors of 1 k, 2 k,and 10 kare connected in parallel. The source is 2A. The currents
through the individual resistors are ________, ________, and ________.
23)
24)
Resistors of 20 kand 10 kare connected in parallel. The current through the 10 kis 5
mA and the current through the 20 kis 2.5 mA. The two parallel resistors are in series
with 30 k.The source voltage is ________.
24)
25)
Two light bulbs are unlabeled and assumed to be the same. You measure 1.67 Aon the 120
Vcircuit. The power of each light bulb must be ________.
25)
26)
Resistors of 4.7 kand 2.2 kare connected in parallel. A6.8 kis in series. The supply is
10 V. The current through the 4.7 kis ________, the current through the 2.2 kis
________, and the voltage across the 6.8 kis ________.
26)
27)
You want to add a150Wflood light to ahouse circuit. This will increase the current by
________.
27)
28)
If the current through R1is 100µA and R2is 1mA and R3is 70 µA, and if the resistors are
connected in parallel, the supply current is ________. You would use ________ to determine
this.
28)
5
29)
You can put aquantity of ________ 100Wbulbs on a20 Acircuit assuming afactor of 1.5
for safety.
29)
30)
A50 , a 200,and a40 resistor are connected in parallel. The current source is 2A. The
power dissipated by the 40 resistor is ________.
30)
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
31)
Energy can be created or destroyed under ideal conditions.
31)
32)
The sum of the currents entering anode must equal the sum of the currents leaving anode.
32)
33)
The current is the same through any element, source or load in aparallel circuit.
33)
34)
The current is the same through any element, source or load in aseries circuit.
34)
35)
KVL works around any closed loop, excluding through the air.
35)
36)
To turn off acurrent source for superposition replace it with ashort circuit.
36)
37)
The voltage is the same across any element, source or load in aseries circuit.
37)
38)
In any closed path, the sum of voltage rises and drops must equal zero.
38)
39)
The voltage is the same across any element, source or load in aparallel circuit.
39)
6
40)
To turn off a voltage source for superposition replace it with ashort.
40)
41)
The total resistance of aparallel circuit is the sum of the resistances.
41)
42)
The current through each component in aparallel circuit is the same.
42)
43)
The current through each component in aseries circuit is the same.
43)
44)
The total resistance of aseries circuit is the sum of the resistances.
44)
45)
The voltage across each component in aparallel circuit is the same.
45)
7
Answer Key
Testname: C3
8