Contractor School Online ®
The premiere national online resource to assist you in passing your Contractor License Exam.

Tell a friend!

Email or Call
Home  |  National Contractor License  |  Request Information  |  Construction Glossary  |  Login

# Colorado-Electrical 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 1 Electrical, Connections, Panel Boards and Grounding What clearance is required for the front of a 208/120 panel? 2 Electrical, Heaters, Conductors, Bonding and Voltage 120/240 V single phase system with single black-red-white conductors (installed in single conduit) select "single set of conductors", 120/208 V 3 phase system with 2 conductors per phase and neutral (installed in 2 parallel conduits) select "_________ conductors per phase in parallel", dc system with 3 positive and 3 negative conductors select "3 conductors per phase in parallel". 3 Electrical Branch Circuits Dual Element Fuse = 4 Electrical, Wires, Cables and Raceways For most 120/240V systems using cables of adequate ampacity, voltage drop is not a concern unless cable lengths are well over a hundred feet. 5 Motor Controls and Occupancies The smallest bonding conductor permitted for pool equipment is No.  ___ AWG. 6 NEC and Electrical Equipment The first step in solving a low voltage problem on a circuit is to leave the voltmeter leads connected across the line, and then begin _________. 7 Electrical Transmission Lines and Communication Lines A messenger that is effectively grounded throughout its length will have the same clearance from the communications facilities that are required for a neutral conductor meeting regarding Rule ___________ in reference to fiber optic supply. 8 Electric Power Conditioning and Mechanical Electrical Lamp pole for exterior use is located 20 ft. away from the building. What type of raceway would be used? 9 Conduits, Voltmeters, Ammeter and Ohmmeter ______ conduit is the only rigid non-metallic conduit that may be used above ground. 10 Protected Premises, Fire Alarm Systems and Fundamentals Every low power radio transmitter will automatically repeat alarm transmission at intervals not exceeding __ seconds until the initiating device is returned to its normal alarm condition. 11 Alarm Inspections, Testing and Maintenance How often shall detectors be tested? 12 Emergency Alarm Communication Systems, Control Functions and Interfaces What do smoke detectors mounted in the air ducts of HVAC systems do? 13 Electrical Miscellaneous, Conductors, Wires, Panels, EMT and Currents Regarding wind pressure calculation: Load in Newtons = 0.613 . (V m/s) 2 . kz . GRF. I . Cf . A(m__) 14 Photovoltaics _________________ is a I-III-VI2 semiconductor material composed of copper, indium, gallium, and selenium. It has a chemical formula of CuInxGa(1-x)Se2 15 Low Voltage Wiring What are closed raceways referred to? 16 Electrical Systems, Cables, Wires and Electrical Sign Installation A sign can be used as a pull box or junction box for adjacent signs, outline lighting systems, or floodlights that ______________.. 17 Part 1 - Fluorescent, LED, HID Fabrication, Tubes and Electrical Flow One type of hysteresis is a simple lag between input and output.If  a sinusoidal input X(t) and output Y(t) that are separated by a phase lag φ: egin{align} X(t) &= X_0 sin omega t Y(t) &= Y_0 sinleft(omega t-phi ight). end{align} Such behavior can occur in linear systems, and a more general form of response is $Y(t) = chi_ ext{i} X(t) + int_0^{infty} Phi_ ext{d} ( au) X(t- au) , mathrm{d} au,$ where $chi_ ext{i}$ is the instantaneous response and $Phi_d( au)$ is the impulse response to an impulse that occurred $au$ time units in the past. In the frequency domain, input and output are related by a complex generalized susceptibility that _____________ be computed from $Phi_d$; it is mathematically equivalent to a transfer function in linear filter theory and analogue signal processing. 18 Part 2 - Fluorescent, LED, HID Fabrication, Tubes and Electrical Flow An ideal dipole consists of two opposite charges with infinitesimal separation. The potential and field of such an ideal dipole are found next as a limiting case of an example of two opposite charges at non-zero separation. Two closely spaced opposite charges have a potential of the form: $phi(mathbf{r})=frac{q}{4 pi varepsilon _0 | mathbf{r}- mathbf{r}_+ |} -frac {q}{4 pi varepsilon _0 | mathbf{r}- mathbf{r}_- | } ,$ with charge separation, d, defined as $mathbf{d} = mathbf{r}_+ - mathbf{r}_- ,$ The position relative to their center of mass (assuming equal masses), R, and the unit vector in the direction of R are given by: ${mathbf{R}} = mathbf{r} - frac{mathbf{r}_+ + mathbf{r}_-}{2} , quad hat{mathbf{R}} = frac {mathbf{R}}{R} ,$ Taylor expansion in d/R (see multipole expansion and quadrupole) allows this potential to be expressed as a series. $phi(mathbf{R}) = frac{1}{4 pi varepsilon _0} frac {qmathbf{d}cdothat{mathbf{R}}}{R^2} + Oleft(frac{d^2}{R^2} ight) approx frac {1}{4 pi varepsilon _0} frac {mathbf{p}cdothat{mathbf{R}}}{R^2} ,$ where higher order terms in the series are vanishing at large distances, R, compared to d. Here, the electric dipole moment p is, as above: $mathbf{p} = qmathbf{d} .$ The result for the dipole potential also can be expressed as: $phi(mathbf{R})=- mathbf{p}cdotmathbf{ abla}frac {1}{4 pi varepsilon _0 R} ,$ which relates the dipole potential to that of a point charge. A key point is that the potential of the dipole falls off faster with distance _____________ than that of the point charge. The electric field of the dipole is the negative gradient of the potential, leading to: $mathbf Eleft(mathbf R ight) = frac{3(mathbf pcdothatmathbf R)hatmathbf R-mathbf p}{4pivarepsilon_0 R^3} .$ 19 Sign Components The voltage and current ratio of autotransformers can be formulated the same as other two-winding transformers: $frac{V_1}{V_2}=frac{N_1}{N_2} = a$ (0

What We Offer  |  Obtaining a Trade License  |  Test Preparation  |  About Us  |  Contact Us