3-9.
3l0.
311.
312.
What instrument is best for
measuring pressure differences in
an atmosphere of air where the
pressure ranges between 31 and 32
inches of mercury?
1.
Bourdon gauge
2.
Schrader gauge
3.
Manometer
4.
Diaphragm gauge
A barometer is used to measure
1.
absolute temperature
2.
atmospheric pressure
3.
relative humidity
4.
steam pressure
The forces in an aneroid barometer
that balance each other are the
1.
2.
3.
4.
The
resistance of a metal box to
stretching or compression plus
the tension in a spring and
atmospheric pressure
resistance of a metal box to
stretching or compression plus
the force exerted by the air in
the box, and the force exerted
by the atmosphere
force exerted by steam under
pressure and the tension in a
spring
force resulting from expansion
in a metal bar and the tension
in a spring
forces in a mercurial barometer
which balance each other are the
1.
2.
3.
4.
weight of a column of mercury
plus the force exerted by the
air in the tube above the
mercury, and the force exerted
by the atmosphere plus 14.7 psi
force exerted by steam under
pressure and the force exerted
by the weight of a column of
mercury
forces exerted by the
atmosphere and the weight of a
column of mercury
weight of a column of mercury,
and the pressure of the vacuum
above
force
the mercury plus the
exerted by the atmosphere
313.
If an airtight container is filled
with steam and then cooled so that
the steam condenses, the pressure
inside the container is reduced
because
1.
2.
3.
4.
a volume of steam weighs less
than an equal volume of water
the pressure on the surface of
a liquid is always zero
the water resulting from the
condensation of the steam
cannot be compressed
a partial vacuum results from
the condensation of the steam
314.
Which of the following instruments
is used for measuring pressures in
the condenser for a steam turbine?
1.
Barometer
2.
Schrader gauge
3.
Manometer
4.
Bourdon tube gauge
Information for items 315 and
o
316:
Pressure measurements are
generally classified as absolute pressure
or gauge pressure.
Absolute pressure is
the total pressure, including that of the
atmosphere; it is the pressure measured
above zero pressure as a reference level.
Gauge pressure is the difference between
absolute pressure and the pressure of the
atmosphere; it is pressure measured above
atmospheric pressure as a reference level.
315.
At sea level, the pressure in a
tire is 24 psi gauge pressure.
The
absolute pressure in the tire is
approximately
1.
39 psi
2.
33 psi
3.
24 psi
4.
9 psi
316.
At sea level, the pressure in an
air tank as measured by an aneroid
barometer is 31 inches of mercury.
How much greater or less than
atmospheric pressure is the
pressure in the air tank?
1.
1 inch more
2.
1 inch less
3.
2 inches less
4.
2 inches more
23