Practice Test Geeks(NECA) National Electrical Contractors Association Practice Test
← All NECA Flashcard Decks

Electrical Theory & Principles Flashcards

7 cards from real NECA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Electrical Theory & Principles flashcards as text

  1. What is the phase relationship between voltage and current in a purely capacitive AC circuit?

    Answer: Current leads voltage by 90°

    In a purely capacitive circuit, current leads voltage by 90° because the capacitor must charge before a voltage develops across it.

  2. Which of the following best describes electric potential difference (voltage)?

    Answer: The work done per unit charge to move charge between two points

    Voltage (potential difference) is defined as the work done per unit charge (W/Q) required to move a charge between two points in an electric field.

  3. A 120V circuit has a load drawing 15A. What is the power consumed?

    Answer: 1,800 W

    Power P = V × I = 120 V × 15 A = 1,800 W (1.8 kW).

  4. In a series RLC circuit at resonance, the impedance is:

    Answer: Minimum and equal to resistance only

    At resonance, inductive reactance equals capacitive reactance and they cancel, leaving only resistance — making impedance minimum and purely resistive.

  5. The skin effect in conductors causes high-frequency AC current to:

    Answer: Concentrate near the outer surface

    The skin effect causes AC current at higher frequencies to flow primarily near the conductor's surface, effectively reducing the useful cross-sectional area and increasing resistance.

  6. What does the term 'impedance' refer to in an AC circuit?

    Answer: Total opposition to AC current flow, combining resistance and reactance

    Impedance (Z) is the total opposition to AC current, expressed in ohms, combining both resistance (R) and reactance (X) as Z = √(R² + X²).

  7. Lenz's Law states that the direction of an induced current is such that it:

    Answer: Opposes the change in flux that caused it

    Lenz's Law states that induced current flows in a direction that opposes the change in magnetic flux that caused it, consistent with conservation of energy.