Final Test Flashcards
Which print shows the face views of the building or residence?
A) Elevation
B) Floor Plan
C) Plot Plan
D) Sectional
Elevation
Three coils with inductance of 2, 4, and 5 henries are connected in parallel. What is the total inductance of the circuit?
A) 358 mH
B) 950 mH
C) 1.05 H
D) 358 H
1.05 H
What would the current through a 150 mH coil connected across a 120-volt 60hz circuit be?
A) 1.06 A
B) 1.96 A
C) 2.12 A
D) 3.14 A
2.12 A
A transformer with more windings on the load side than on the line side is known as a ____ transformer.
A) Primary load
B) Secondary load
C) Step-down
D) Step-up
Step-up
Dwelling unit receptacle outlets serving kitchen wall countertop spaces shall be installed so that no point along the wall is more than ___ from a receptacle outlet.
A) 12”
B) 18”
C) 24”
D) 48”
24”
The ability of an inductor in a transformer to generate inductive reactance, which opposes changes in the current direction is called ___.
A) Impedance
B) Mutual Inductance
C) Reactance
D) Self-Inductance
Self-inductance
The symbol “L” is used in a drawing to identify ___.
A) Inductance
B) Inductive reactance
C) Unit of frequency
D) Unit of inductance
Inductance
A transformer has a turns ratio of 1:2. By applying 480 volts to the primary of this transformer, the secondary voltage will be ___.
A) 208 V
B) 240 V
C) 720 V
D) 960 V
960 V
(Circle with three parallel lines coming out the left side, and an “R” in the bottom right corner)
What does this symbol represent?
A) 125 V duplex outlet
B) 125 V special outlet
C) 250 V range outlet
D) 250 V recessed outlet
250 V range outlet
The capacitive reactance of a circuit is determined by the ___?
A) current and voltage
B) frequency and capacitance
C) impedance minus inductance
D) inductance minus resistance
frequency and capacitance
Where the NEC requires that one piece of equipment shall be “in-sight” from another piece of equipment, the specified distance shall be no more than ___ between equipment.
A) 25’
B) 50’
C) 75’
D) 100’
50’
A power transmission line has a current of 84 amps flowing through the conductor, and the conductor has a resistance of 11 ohms. What is the power flowing through the transmission line?
A) 642 W
B) 924 W
C) 10,164 W
D) 77,616 W
77,616 W
If the frequency is increased in a series RL circuit, the impedance will ___.
A) decrease
B) increase
C) increase proportionally to the current
D) remain the same
increase
Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform (illegible)
???
If a current of 30 amperes is measured on B phase of a wye-connected transformer, the current through the B winding will be
A) 15 A
B) 17.4 A
C) 30 A
D) 51.9 A
30 A
Xc = 1 / (2 * pi * f * C )
This formula is used to calculate ___.
A) Capacitive reactance
B) Impedance in a series LCR
C) Inductive reactance
D) Ohm’s Law
Capacitive reactance
Which item is not measured in ohms?
A) Capacitance
B) Impedance
C) Inductive Reactance
D) Resistance
Capacitance (farads)
If a 3-phase, single-voltage, wye-connected transformer is supplied by 4160 volts, the voltage across each winding will be ___.
A) 1680 V
B) 2405 V
C) 4160 V
D) 7197 V
2405 V
(source voltage over root 3)
___ is a direct result of an arc-blast event.
A) Fire
B) Heat
C) Light
D) Pressure
Pressure
Which item listed is classified as a fitting in reference to a wiring system?
A) Fuse
B) Lamp holder
C) Locknut
D) Receptacle
Receptacle
A 48-microfarad capacitor has a voltage drop of 30 volts across it in a 60hz AC circuit. How much current is flowing across it?
A) 542 mA
B) 625 mA
C) 540 A
D) 1670 A
542 mA
(Find capacitive reactance, then use that to find amps)
The load for household electric clothes dryers in a dwelling unit shall be ___ or the nameplate rating, whichever is higher.
A) 3500 W (VA)
B) 4000 W (VA)
C) 4500 W (VA)
D) 5000 W (VA)
5000 W (VA)
Where buildings exceed three stories or 50 feet in height, overhead lines shall be arranged, where practical, so that … either adjacent to the buildings or beggining not over ___ from them to facilitate the raising of ladders when necessary.
A) 3’ / 6’
B) 4’ / 8’
C) 6’ / 8’
D) 8’ / 10’
6’ / 8’
(Right triangle with sides of 10 and 12 units, and a hypotenuse of z units)
The length of side Z is ___.
A) 4.7
B) 15.6
C) 16.5
D) 17.8
15.6