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WorksheetsJM02JD9F8VJD
Total questions: 50
Worksheet time: 50mins
Name
Class
Date
1.
Frequency is measured in _____.
a)
hertz
b)
voltage
c)
rpm
d)
foot pounds
2.
Which of the following would cause the most power to be dissipated in the form of heat?
a)
XL
b)
XC
c)
resonance
d)
resistance
3.
____ is the combined opposition to current by resistance and reactance.
a)
Q
b)
Z
c)
XC
d)
(I^2)R
4.
An electrician in the industry would first check the _____ to correct a low power factor.
a)
resistance
b)
hysteresis
c)
inductive load
d)
reluctance
5.
Single conductor cable runs within a building are generally more common than multicable runs because _____.
a)
of conduit fill
b)
of the temperature
c)
the splicing is easier
d)
the weight is evenly distributed
6.
_____ has the highest electrical breakdown strength and longest life over all other materials used for insulation.
a)
Rubber insulation
b)
woven cloth
c)
impregnated paper
d)
thermoplastic
7.
Voltage in a generator is produced by _____.
a)
resonance
b)
pressure
c)
cutting lines of force
d)
chemical
8.
To adjust the voltage generated by a constant speed DC generator, you would change the ____.
a)
stator
b)
slip rings
c)
brushes
d)
field current
9.
The generator which is best suited for electroplating power is a _____ generator.
a)
split-phase
b)
six pole
c)
separately excited
d)
compound
10.
To change the rotattion of a DC motor, you would _____.
a)
reverse capacitor leads
b)
reverse A1 and A2
c)
reverse commutator
d)
reverse F1 and F2
11.
Frequency is determined by the _____ of an alternator. [I. Size, II. Number of poles, III.Voltage, IV. Rotation speed of the armature]
a)
II only
b)
II and III only
c)
II and IV only
d)
I, II, and IV only
12.
An example of a "made" electrode would be _____.
a)
metallic water pipe
b)
metal frame of a building
c)
concrete-encased
d)
ground rod
13.
Illumination is measured in _____.
a)
luminous flux
b)
lumens
c)
temperature
d)
foot candles
14.
A motor enclosure designed and constructed to contain sparks or flashes that may ignite surrounding gas or vapor is called _____.
a)
non-ventilated
b)
encapsulated
c)
explosion proof
d)
water cooled
15.
The output of a 3-phase transformer is measured in units called ____.
a)
watts
b)
volt-amps
c)
impedance
d)
turns-ratio
16.
Three horsepower is equivalent to _____ watts.
a)
764
b)
2292
c)
2238
d)
none of these
17.
Sometimes, copper conductors are coated (tinned) to help prevent _____.
a)
higher resistances
b)
mechanical damage
c)
capacitive reactance
d)
chemical reaction
18.
A wheatstone bridge is used to measure _____ resistance. [I. low, II. Medium, III. High]
a)
I only
b)
II and III only
c)
III only
d)
II only
19.
To check the voltage to ground, you would check from ______.
a)
the breaker to the cabinet
b)
hot to neutral
c)
the breaker to the grounding terminal
d)
all of these
20.
The inductive action that causes current to flow on the outside surface of a conductor is known as the _____.
a)
corona effect
b)
skin effect
c)
electrolitic action
d)
DC reactance
21.
Electrical continuity is required by the electrical code for metallic conduit ______.
a)
to assure equipment grounding
b)
to reduce static electricity
c)
to reduce inductive heat
d)
to trace electrical wiring
22.
The resistance of an open circuit is equal to ____.
a)
less than one ohm
b)
zero
c)
infinity
d)
none of these
23.
An electrical timer switch for lighting is normallu connected in ____ with the lighting circuit being controlled.
a)
series
b)
parallel
c)
sequence
d)
tandem
24.
The definition of ampacity is _____.
a)
the current-carrying capacity of conductors expressed in volt-amps
b)
the current-carrying capacity expressed in amperes
c)
the current-carrying capacity of conductors expressed in wattage
d)
the current in amperes a conductor can carry continuously under the conditions of use without exceeding its temperature rating
25.
The grounded conductor would connect to the ____ of a lampholder.
a)
screw shell
b)
filament
c)
base contact
d)
lead in wire
26.
A three-phase, 6-pole AC alternator 34 kVA, on a Y-connected system. During one complete mechanical rotation (360 degrees) will have ____ electrical rotations.
a)
1
b)
1.5
c)
3
d)
12
27.
The voltage per turn of the primary of a transformer is ___ the voltage per turn of the secondary.
a)
more than
b)
the same as
c)
less than
d)
none of these
28.
A single concrete-encases electrode shall be augmeneted by one additional electrode if it does not have a resistance to ground of _____.
a)
25 ohms
b)
30 ohms
c)
50 ohms
d)
not a Code requirement
29.
Which of the following is not true about alternating current?
a)
develops eddy current
b)
it can be transformed
c)
is suitablefor charging batteries
d)
interferes with communication lines
30.
On a 120V 1-phase circuit, ground fault protection for personnel operates on the principal of unbalanced current between _____.
a)
the grounded and ungrounded conductor
b)
the ungrounded conductors
c)
the grounding conductor and the neutral conductor
d)
the service disconnect and the branch circuit
31.
In a 3-phase circuit, how many electrical degrees separate each phase?
a)
360
b)
180
c)
120
d)
90
32.
_____ duty is a type of service where both the load and the time intervals may have wide variations.
a)
Continuous
b)
periodic
c)
intermittent
d)
varying
33.
The definition of ambient temperature is _____.
a)
the temperature of the conductor
b)
the insulation rating of the conductor
c)
the temperature of the area surrounding the conductor
d)
the maximum heat the insulation can be used within
34.
As the power factor of a circuit is increased _____.
a)
reactive power is decreased
b)
active power is decreased
c)
reactive power is increased
d)
both active and reactive power are increased
35.
Tinning rubber insulated twisted cable is done to ____.
a)
make the strands stronger
b)
prevent the chemical reactions between the copper and the rubber
c)
increase the resistance
d)
meet NEMA requirements
36.
A negatively charged body has _____.
a)
excess of electrons
b)
excess of neutrons
c)
deficit of electrons
d)
deficit of neutrons
37.
A fluorescent light that blinks "on" and "off" repeatly may in time ____.
a)
cause the fuse to blow
b)
cause the switch to wear out
c)
cause the wire to melt
d)
result in damage to the ballast
38.
Electrical appliances are connected in parallel because it ______
a)
makes the operation of appliances in independent of each other
b)
results in reduced power loss
c)
is a simple circuit
d)
draws less current
39.
What relationship determines the efficiency of electrical equipment?
a)
The power input divided by the output
b)
The volt-amps x the wattage
c)
The va divided bt the pf
d)
The power output divided by the input
40.
What is the formula to find watt hours?
a)
E x T x 1000
b)
E x I x T
c)
I x E x T/1000
d)
E x T x phase/1000
41.
Of the six ways of producing emf, which method is used the least?
a)
pressure
b)
solar
c)
chemical reaction
d)
friction
42.
The voltage produced by electromagnetic induction is controlled by ____.
a)
the number of lines of flux cut per second
b)
eddy currents
c)
the size of the magnet
d)
the number of turns
43.
As the power factor of a circuit is increased _____.
a)
reactive power is decreased
b)
active power is decreased
c)
reactive power is increased
d)
both active and reactive power are increased
44.
The breakdown voltage of an insulation depends upon _____ value of AC voltage.
a)
r.m.s
b)
effective
c)
peak
d)
1.732 of peak
45.
The AC system is preferred to the DC system because ______
a)
DC voltage cannot be used for domestic appliances
b)
DC motors do not have speed control
c)
AC voltages can be easily changed in magnitude
d)
high-votlage AC transmission is less efficient
46.
DC series motors are used in appliactions where _____ is required.
a)
constant speed
b)
high starting torque
c)
low no-load speed
d)
none of these
47.
Basically all electric motors operate on the principle of repulsion or ____.
a)
magnetism
b)
induction
c)
resistance
d)
capacitance
48.
A capacitor opposes ____.
a)
both a change in votlage and current
b)
change in current
c)
change in voltage
d)
none of these
49.
The armature current drawn by any DC motor is proportional to the _____.
a)
motor speed
b)
voltage applied
c)
flux required
d)
torque applied
50.
The greatest voltage drop in a circuit will occur when the ____ the current flow through that part of the circuit.
a)
greater
b)
slower
c)
faster
d)
lower
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