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# Vermont-Electrical Master Online Practice Test

These are actual questions from our online practice test.

We have included a question from each chapter of the test. Every question will be multiple choice. The answers are not included with the sample.

## Sample Questions

 # Chapter Title Question 7 AC/DC/Capacitance/Inductor/SWER 1 Inductors in a parallel configuration each have the same potential difference (voltage). To find their total equivalent inductance (Leq): ${displaystyle {frac {1}{L_{mathrm {eq} }}}={frac {1}{L_{1}}}+{frac {1}{L_{2}}}+cdots +{frac {1}{L_{n}}}}$ The current through inductors in series stays the same, but the voltage across each inductor can be different. The sum of the potential differences (voltage) is equal to the total voltage. To find their total inductance: ${displaystyle L_{mathrm {eq} }=L_{1}+L_{2}+cdots +L_{n},!}$ These simple relationships hold true only when there is no mutual coupling of magnetic fields between individual inductors. 13 Basic Bid Preparation/Estimating/Blueprint Reading What symbol is on the end of dimension lines limit each dimension on blueprints? 1 Capacity Factor/Unit Load Calculations 1/Demand Factor/Dielectric Tunable dielectrics are insulators whose ability to store electrical charge changes when a voltage is applied. Strontium titanate (SrTiO 3) is used for devices operating at low temperatures, while barium strontium titanate (Ba 1−xSr xTiO 3) substitutes for room temperature devices. Other potential materials include microwave dielectrics and carbon nanotube (CNT) composites. In 2013 multi-sheet layers of strontium titanate interleaved with single layers of strontium oxide produced a dielectric capable of operating at up to 125 GHz. The material was created via molecular beam epitaxy. The two have mismatched crystal spacing that produces strain within the strontium titanate layer that makes it less stable and tunable. Systems such as Ba 1−xSr xTiO 3 have a paraelectric–ferroelectric transition just below ambient temperature, providing __________ tunability. Such films suffer significant losses arising from defects. 4 Conductor Sizing/Protection Calculations/AC Power Plugs/Sockets A blade connector is a type of single wire connection using a flat conductive blade which is inserted into a blade receptacle. Usually both blade connector and blade receptacle have wires attached to them either through of the wire to the blade or __________ of the blade to the wire. In some cases the blade is an integral manufactured part of a component (such as a switch or a speaker unit), and a blade receptacle is pushed onto the blade to form a connection. 2 Distribution Feeder Regulation/Delta/Delta wye Transformers/Voltage Drop/Voltage Divider/Voltage Regulation/Current Divider One case of voltage regulation is in a transformer. The unideal components of the transformer cause a change in voltage when current flows. Under no load, when no current flows through the secondary coils, Vnl is given by the ideal model, where VS = VP*NS/NP. Looking at the equivalent circuit and neglecting the shunt components, as is a reasonable approximation, one can refer all resistance and reactance to the secondary side and clearly see that the secondary voltage at no load will indeed be given by the ideal model. When the transformer delivers full load, a voltage drop occurs over the winding resistance, causing the terminal voltage across the load to be lower than anticipated. This leads to a __________ voltage regulation which must be considered in use of the transformer. 12 Employees/Contractors/Insurance/Safety OSHA form 300, log and summary of occupational injury must be kept for how many years? 8 Ground/Earthing System/Three-Phase An ungrounded electrical box, appliance, power tool, or extension cord could become a danger if there is no path to ground, except through you. Without a ground wire, your body may complete the ground path and you may be shocked or electrocuted. In older homes with cloth wrapped wire or in homes with knob and __________ wiring, this is the case. Newer appliances and some tools come equipped with a three-pronged cord, incorporating a ground for protection. 9 HV Circuit Breaker Testing/Unit Load Calculations 2/Service Load Calculations/Optional Methods/SWER 2/Motor Constant Where should you mount your transducer? You should look for an easily attachable place where your transducer will move in conjunction with the interrupter(s). You should also try to mount the transducer to a solid piece of metal that won’t vibrate during operation of the circuit breaker. The closer you are to the interrupter without mechanical linkages in between, the more accurate your travel __________ will become. Once a transducer mounting spot is established, you should continue to test it at this spot for accurate trending purposes. 10 Inductance/Impedance/Connectors In order to simplify calculations, sinusoidal voltage and current waves are commonly represented as complex-valued functions of time denoted as {displaystyle scriptstyle V} and {displaystyle scriptstyle I} . {displaystyle {egin{aligned}V&=|V|e^{j(omega t+phi _{V})},I&=|I|e^{j(omega t+phi _{I})}.end{aligned}}} The impedance of a bipolar circuit is defined as the ratio of these quantities: ${displaystyle Z={frac {V}{I}}={frac {|V|}{|I|}}e^{j(phi _{V}-phi _{I})}.}$ Hence, denoting {displaystyle heta =phi _{V}-phi _{I}} , we have {displaystyle {egin{aligned}|V|&=|I||Z|,phi _{V}&=phi _{I}+ heta .end{aligned}}} The magnitude equation is the familiar Ohm's law applied to the voltage and current amplitudes, while the second equation defines the __________ relationship. 6 Junction Boxes/Raceways/Conduit Bodies/Reclosers/Multiway Switching/Camlock If the PVC coating is UL listed as the primary corrosion protection, does that mean the conduit complies with NEMA RN-1? 5 MIL-STD-1553/ACCC Conductor/Motors/Transformers/Circuit Breaker/Brushed DC Electric Motor/Short Circuit MIL-STD-1553B does not specify the length of the bus. However, the maximum length of bus is directly related to the gauge of the cable conductor and time delay of the transmitted signal. A smaller conductor attenuates the signal more than a larger conductor. Typical propagation delay for a 1553B cable is 1.6 __________ per foot. Thus, the end-to-end 100-foot bus (30 m) would have a 160 nanosecond propagation delay, which is equal to the average rise time of a 1553B signal. According to MIL-HDBK-1553A, when a signal's propagation delay time is more than 50% of the rise or fall time, it is necessary to consider transmission line effects. This delay time is proportional to the distance propagated. 11 OSHA Safety/Training/Asbestos/Code of Federal Regulations/Title 29, Part 1926 For all Class I jobs involving the removal of more than __________ linear or 10 square feet of thermal system insulation or surfacing material; for all other Class I jobs, where the employer cannot produce a negative exposure assessment pursuant, or where employees are working in areas adjacent to the regulated area, while the Class I work is being performed, the employer shall use one of the following methods to ensure that airborne asbestos does not migrate from the regulated area: 3 Theory Incidence matrix: The ${displaystyle n_{t} imes n_{f}}$ matrix ${displaystyle mathbf {A_{a}} }$ is called node-to-__________ incidence matrix for the matrix elements ${displaystyle a_{ij}}$ being ${displaystyle a_{ij}={egin{cases}1,&{ ext{if flow }}j{ ext{ leaves node }}i-1,&{ ext{if flow }}j{ ext{ enters node }}i,&{ ext{if flow }}j{ ext{ is not incident with node }}iend{cases}}}$ A reference or datum node ${displaystyle P_{0}}$ is introduced to represent the environment and connected to all dynamic nodes and terminals. The ${displaystyle (n_{t}-1) imes n_{f}}$ matrix ${displaystyle mathbf {A} }$ , where the row that contains the elements ${displaystyle a_{0j}}$ of the reference node ${displaystyle P_{0}}$ is eliminated, is called reduced incidence matrix. The conservation laws (KCL) in vector-matrix form: ${displaystyle mathbf {A} mathbf {F} =mathbf {0} }$ The uniqueness condition for the potentials (KVL) in vector-matrix form: ${displaystyle mathbf {W} =mathbf {A^{T}} mathbf {w} }$ where ${displaystyle w_{k}}$ are the absolute potentials at the nodes to the reference node ${displaystyle P_{0}}$ . Proof: Using KVL: {displaystyle {egin{aligned}mathbf {W^{T}} mathbf {F} =mathbf {(A^{T}w)^{T}} mathbf {F} =mathbf {(w^{T}A)} mathbf {F} =mathbf {w^{T}AF} =mathbf {0} end{aligned}}} because ${displaystyle mathbf {AF} =mathbf {0} }$ by KCL. So: ${displaystyle sum _{k=1}^{b}W_{k}F_{k}=mathbf {W^{T}} mathbf {F} =0}$ 99 USA Dig Alert The ##DIG_ALERT_COMPANY## markings are valid __________.