Texas Journeyman Electrician Exam, Definitions, Theory and Plans: all 108 questions

All questions from the Definitions, Theory and Plans section for Texas Journeyman Electrician Exam, each with the correct answer.

1001If the resistance of a circuit stays the same and the applied voltage is increased, what happens to the current?
1002A heater operates on a fixed supply voltage. If its element resistance were doubled, the current would:
1003If the current through a fixed resistance is doubled, the power dissipated in that resistance becomes:
1004A resistive load draws 10 amperes from a 120-volt supply. How much power does it use?
1005Which unit is used to express electrical resistance?
1006In a series circuit, which quantity is the same at every component?
1007Three resistors of 10, 20 and 30 ohms are connected in series. What is the total resistance?
1008In a parallel circuit, which quantity is the same across every branch?
1009Two 10-ohm resistors are connected in parallel. What is the combined resistance?
1010When another branch is added to a parallel circuit, the total resistance of the circuit:
1011Several lamps are wired in series. If one lamp filament opens, what happens to the others?
1012Kirchhoff's current law states that at any junction in a circuit:
1013Kirchhoff's voltage law states that around any closed loop:
1014Four 1.5-volt cells are connected in series. What is the output voltage?
1015Identical batteries connected in parallel will:
1016One horsepower is equal to approximately:
1017What does a kilowatt-hour measure?
1018The efficiency of a motor is found by:
1019How does the resistance of a conductor change if its length is doubled and the size stays the same?
1020For copper conductors, how does resistance normally change as conductor temperature rises?
1021A circular mil is defined as the area of a circle with a diameter of:
1022Compared with a copper conductor of the same size and length, an aluminum conductor has:
1023Which of the following metals is the best electrical conductor?
1024In an AC circuit, the tendency of current to concentrate near the outer surface of a conductor is called:
1025To reduce voltage drop on a long branch circuit without changing the load, an electrician can:
1026A material that offers very high resistance to current flow, such as glass or rubber, is called:
1027In the United States, the standard frequency of the utility supply is:
1028The RMS (effective) value of an AC voltage is the value that:
1029A 120-volt RMS sine wave has a peak voltage of approximately:
1030Power factor in an AC circuit is the ratio of:
1031In a purely resistive AC circuit, such as an incandescent lamp, the power factor is:
1032In a circuit that is mainly inductive, such as a motor winding, the current:
1033In a circuit that is mainly capacitive, the current:
1034A plant with many induction motors has a low lagging power factor. What is commonly added to improve it?
1035As the supply frequency increases, the inductive reactance of a coil:
1036As the supply frequency increases, the capacitive reactance of a capacitor:
1037The total opposition to current flow in an AC circuit, combining resistance and reactance, is called:
1038A series AC circuit has 3 ohms of resistance and 4 ohms of inductive reactance. What is the impedance?
1039The unit of inductance is the:
1040Once fully charged in a steady DC circuit, a capacitor:
1041Capacitors connected in parallel have a total capacitance that is:
1042A series RLC circuit is at resonance when:
1043Volt-amperes (VA) in an AC circuit represent:
1044In a three-phase system, the three voltages are displaced from each other by:
1045In a wye-connected system, the line-to-line voltage equals the line-to-neutral voltage multiplied by:
1046On a 208Y/120-volt three-phase, four-wire system, what voltage is measured from any phase conductor to the neutral?
1047On a 480Y/277-volt system, what is the voltage between any two phase conductors?
1048In a delta-connected transformer winding, the line current equals the phase (winding) current multiplied by:
1049On a 240/120-volt three-phase, four-wire delta system with a center-tapped winding, the high leg measures approximately how many volts to the neutral?
1050On a balanced three-phase, four-wire wye system serving only linear resistive loads, the neutral current is:
1051On a wye system serving many computers and LED drivers, which harmonics add together in the neutral instead of canceling?
1052Which expression gives the true power of a balanced three-phase load?
1053How is the rotation of a three-phase induction motor reversed?
1054What is the synchronous speed of a 4-pole induction motor on a 60 Hz supply?
1055The difference between the synchronous speed of the rotating field and the actual rotor speed of an induction motor is called:
1056A transformer has 1,000 turns on the primary and 100 turns on the secondary. If 480 volts is applied to the primary, the secondary voltage is:
1057In an ideal step-down transformer, compared with the primary side, the secondary side has:
1058Why will a transformer not operate on steady direct current?
1059Transformer cores are made of thin laminated steel sheets mainly to reduce:
1060Transformers are rated in kVA rather than kW because:
1061A transformer that uses a single winding for both primary and secondary, with no electrical isolation between them, is:
1062Two magnets are placed with their north poles facing each other. They will:
1063Current flowing through a conductor creates:
1064A voltage is induced in a conductor when it moves through a magnetic field and cuts the lines of flux. This principle is called:
1065Lenz's law states that an induced current flows in a direction that:
1066Which material is best suited for the core of an electromagnet because it magnetizes easily and has high permeability?
1067A generator converts:
1068A diode is a semiconductor device that:
1069An insulation resistance tester (megohmmeter or megger) checks insulation by:
1070An electrician places a clamp-on ammeter around both the hot and neutral conductors of a single-phase, two-wire circuit carrying a load. The meter will read:
1071How must a voltmeter be connected to measure the voltage across a load?
1072Why must an ohmmeter be used only on a de-energized circuit?
1073Which instrument directly measures true power in watts?
1074A floor plan is drawn at a scale of 1/4 inch = 1 foot. A conduit run measures 6 inches on the drawing. How long is the actual run?
1075On an electrical floor plan, a small circle with two short parallel lines through it typically represents:
1076On an electrical plan, the letter S with a small subscript 3 next to it indicates:
1077On a branch circuit layout, a line ending in an arrowhead with a circuit number beside it means:
1078On a lighting plan, a curved dashed line drawn from a switch to a luminaire shows:
1079A diagram that uses a single line to represent a three-phase circuit and shows the service, feeders, transformers and panels is called:
1080A panel schedule on a set of electrical drawings normally lists:
1081The abbreviation WP next to a receptacle symbol on a plan usually means the receptacle must be:
1082Under the NEC definition, equipment is readily accessible when it can be reached for operation or inspection:
1083As defined in the NEC, a continuous load is one where the maximum current is expected to continue for:
1084Which set of features makes a space a dwelling unit under the NEC?
1085According to the NEC, a qualified person is someone who:
1088The circuit conductors between the final overcurrent device protecting the circuit and the outlets are called:
1089Conductors running from the service equipment to a subpanel that contains the final branch-circuit breakers are classified as:
1090Ampacity is defined in the NEC as the maximum current a conductor can carry continuously:
1091In the NEC, the term approved means:
1092Equipment that has a label, symbol or identifying mark of an organization acceptable to the AHJ that maintains periodic inspection of its production is described as:
1093Under the NEC, operation of equipment in excess of its normal full-load rating that would cause damaging overheating if it persisted is called:
1094Under the NEC, a disconnect is considered in sight from the equipment it serves when it is visible and not more than:
1095A branch circuit with two or more ungrounded conductors having a voltage between them and a grounded conductor with equal voltage to each ungrounded conductor is a:
1096A building-supplied transformer whose secondary has no direct electrical connection to the supply conductors, except through grounding and bonding connections, creates:
1097The point of connection between the facilities of the serving utility and the premises wiring is called the:
1098A partially protected location under a canopy or a roofed open porch is classified in the NEC as a:
1103NEC 110.3(B) requires that listed or labeled equipment be installed and used:
1104Unless the equipment is listed and marked otherwise, terminations for circuits rated 100 amperes or less (or 14 AWG through 1 AWG conductors) are based on which conductor temperature rating?
1105For circuits rated over 100 amperes, or conductors larger than 1 AWG, terminations are generally based on which conductor temperature column?
1106Copper and aluminum conductors may be joined in the same terminal or splicing connector only when:
1108The required depth of working space in front of a 120/240-volt panelboard (150 volts or less to ground) is, for all conditions:
1109A 480Y/277-volt panelboard has exposed live parts on one side of the working space and a grounded concrete wall on the other (Condition 2). What is the minimum depth of working space?
1110Equipment at 277 volts to ground has exposed live parts on both sides of the working space (Condition 3). The minimum working space depth is:
1111What is the minimum width of the working space in front of electrical equipment covered by 110.26(A)?
1112For service equipment and panelboards, the minimum headroom of the working space is generally:
1113A homeowner stacks storage boxes in the working space in front of a panelboard. Under 110.26, this is:
1115NEC 110.12 requires electrical equipment to be installed:
1116Equipment intended to interrupt current at fault levels must have an interrupting rating that is:

Texas Journeyman Electrician Exam, Definitions, Theory and Plans: all 108 questions

More topics