Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
Aresistor load dissipates 200mW when 9 V is applied. The color code is
1)
A)
Yellow–Green–Brown–Gold.
B)
Yellow–Yellow–Brown–Gold.
C)
Orange–White–Brown–Gold.
D)
Orange–Violet–Brown–Gold.
2)
Ohm‘s law states that
2)
A)
V = IR
B)
V = I
R
C)
P = V
I
D)
P = VI
3)
The resistance of a75 Wlight bulb on a120 Vsystem is
3)
A)
75
B)
0.625
C)
192
D)
1.6
4)
A150Wlight bulb is on for 12 hours each night to illuminate aflag. The energy cost is $0.062/kWh.
The cost to operate this light for 365 days is
4)
A)
$657.21
B)
$40.73
C)
$400.73
D)
$4.07
5)
You measure 17 mA of current through aresistor that has 35 Vacross it. The color code of the
resistor is
5)
A)
Red–Red–Red–Gold.
B)
Red–Red–Brown–Gold.
C)
Red–Red–Red–Silver.
D)
Red–Brown–Brown–Gold.
1
6)
A 5 hp motor is operating on a220Vsystem. The current is
6)
A)
17.0 A
B)
10 A
C)
22.7 mA
D)
15 A
7)
Anichrome wire that is 0.3 ft long has aresistance of 1 k.The wire radius is
7)
A)
1.7 cm
B)
0.21 in.
C)
0.914 cm
D)
0.53 in.
B
8)
Resistors are used to limit
8)
A)
heat.
B)
current.
C)
temperature.
D)
power.
B
9)
If aresistor measures 468,the most likely color code is
9)
A)
Yellow–Blue–Brown–Silver.
B)
Yellow–Yellow–Brown–Gold.
C)
Yellow–Violet–Black–Gold.
D)
Yellow–Green–Black–Silver.
A
10)
There is 2 V across a50 resistor. The power dissipated is
10)
A)
8mW
B)
40 mW
C)
80 mW
D)
100mW
C
11)
A10 AWG solid copper wire hasaresistance of 2.The wire length is
11)
A)
60.8 ft
B)
6.1 m
C)
200inches
D)
60.8 m
D
2
A
12)
Acopper wire has aresistance of 200 m.The cross–sectional area is 5mm2.The length of the wire
is
12)
A)
0.15 mm
B)
0.145 cm
C)
5.8 cm
D)
581mm
13)
If aresistor measures 1221 ,the most likely color code is
13)
A)
Brown–Red–Brown–Silver.
B)
Brown–Red–Red–Gold.
C)
Brown–Red–Red–Brown.
D)
Brown–Red–Brown–Gold.
14)
Resistors are
14)
A)
used to control temperature.
B)
an important specific example of resistance.
C)
the only components that have resistance.
D)
Both Band C
15)
Acircuit operating on 12 Vdraws 20 mA. The load resistance is
15)
A)
0.6
B)
0.24
C)
600
D)
240
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
16)
The resistance of asilver bar that is 0.2 in. x0.2 in. and 18 in. long is ________.
16)
17)
The resistance of a 3 V, 0.75 Wlamp while on is ________.
17)
18)
The resistance of agold bar that is 0.4 in. x0.4 in. and 36 in. long is ________.
18)
3
19)
If 12 Vis applied to aload of 2 k,the current is ________.
19)
20)
If the color code is red–red–red–gold, the nominal value is ________, the lowest
in–tolerance value is ________ and the highest in–tolerance value is ________.
20)
21)
If 12 Vis applied to a 3 W light bulb, the current is ________ and the “on” resistance is
________.
21)
22)
Aresistor with acolor code of brown–black–red–silver measures 1.25 k.The resistor is
________ percent from nominal.
22)
23)
If the voltage across a50 resistor is 16.7 V, the power dissipated is ________.
23)
24)
Aresistor has acolor code of blue–gray–red–silver. The nominal value is ________ and the
acceptable range is ________ to ________.
24)
25)
The resistance for acopper conductor that is 2ft long and has across–section of 0.25 in. x
0.25 in. is ________.
25)
26)
The resistance for 100 feet of solid 12 AWG copper wire is ________.
26)
27)
The resistance of acopper bar that is 0.3 in. x0.3 in. and 24 in. long is ________.
27)
28)
The current needed to operate a12 hp motor operating at 220Vis ________.
28)
29)
Aresistor measures 1.270 kand is in tolerance. The color code is ________.
29)
4
30)
Aresistor has a voltage across of 3 V and current of 3mA through. The power dissipated is
________ and the resistance is ________.
30)
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
31)
Power is directly proportional to voltage and indirectly proportional to current.
31)
32)
Energy is defined as the ability to do work.
32)
33)
Wire resistance increases as temperature increases.
33)
34)
The resistance, R, is directly proportional to cross–sectional area, A.
34)
35)
Ohm‘s law states P = IR.
35)
36)
Resistors are used to limit current.
36)
37)
Acolor code of Yellow–Green–Orange–Silver indicates aresistor value of 45 k±20%.
37)
38)
A 1 k±5% resistor would have acolor code of Brown–Black–Red–Gold.
38)
39)
Insulators often have valence shells that are empty.
39)
40)
Wire resistance, R, is directly proportional to the conductor length, l.
40)
41)
The trend between current and resistance is an inverse relationship.
41)
5
42)
Power is how fast energy is used or generated.
42)
43)
If resistance is held constant and the voltage is increased, current will decrease.
43)
44)
The electrical force needed to push/pull electrons is called voltage.
44)
45)
The current through a100Wlight bulb on a120Vsystem is 1
2amp.
45)
6
Answer Key
Testname: C2
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