39.
Generally, the electrical or mechanical systems on which air flow measuring
instruments are based are quite sensitive to _________; this is one reason that
such instruments require periodic_______________ .
a. Touch; watering.
c. Noise; static pressure.
d. Pressure; pitot tube cleaning.
40.
An inch of water is:
a. A unit of pressure equal to the pressure exerted by a column of liquid one
inch high at a standard temperature.
b. A unit of pressure more than the pressure exerted by a column of liquid one
inch high at a standard temperature.
c.
A formula used to help calibrate instruments.
d. Read directly on a meter, which is actuated by a change in voltage.
41.
Which statement is correct concerning anemometer accuracy?
a. Relatively wide probes and fittings can also be used to measure air velocities
within the system.
b. The accuracy in determining duct velocities or flow rates will be dependent
upon proper locations and number of measurements taken in traversing the
duct.
c.
The difference between the velocity pressure and the static pressure is the
total pressure.
d. All of the above.
MD0165
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