Practice Test GeeksBOC - Building Operator Certification Practice Test
← All BOC Flashcard Decks

Technical Measurements Flashcards

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

Read the first 7 Technical Measurements flashcards as text

  1. Which instrument uses dry-bulb and wet-bulb thermometers to determine relative humidity?

    Answer: Sling psychrometer

    A sling psychrometer reads dry-bulb and wet-bulb temperatures, which are plotted or tabulated to find relative humidity.

  2. Which instrument is best suited for reading low duct static pressures in inches of water column?

    Answer: Inclined manometer

    Inclined manometers (and Magnehelic gauges) accurately read the small pressures found in air ducts.

  3. A Pitot tube connected to a manometer in a duct directly measures which quantity?

    Answer: Velocity pressure (total minus static)

    A Pitot tube senses total and static pressure; the difference is velocity pressure, used to calculate air velocity.

  4. Which meter is used to test the insulation resistance of motor windings?

    Answer: Megohmmeter

    A megohmmeter applies a high DC voltage to measure insulation resistance in megohms.

  5. For a clamp-on ammeter to read current correctly, how should it be placed?

    Answer: Around one conductor only

    Clamping both conductors cancels the magnetic fields, so only one conductor should be enclosed.

  6. How does a platinum RTD respond to rising temperature?

    Answer: Its resistance increases

    RTDs have a positive temperature coefficient, so resistance rises as temperature rises.

  7. What principle does a thermocouple use to measure temperature?

    Answer: Voltage produced at the junction of two dissimilar metals

    A thermocouple generates a small voltage proportional to temperature difference at junctions of dissimilar metals (Seebeck effect).