Term
36. The dew point is:
a. the temp at which moisture will start to go into the air.
b. the pressure at which moisture will condense out of the air.
c. the temp at which moisture will condense out of the air.
d. the temp at which a dock will be totally dry |
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Definition
| c. the temp at which moisture will condense out of the air. 3-3 |
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Term
37. the dry bulb temperature is:
a. an indication of the moisture content of the air
b. an indication of the total enthalpy of the air
c. an indication of the sensible heat content of the air
d. an indication of the humidity in the air |
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Definition
| c. an indication of the sensible heat content of the air 3-3 |
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Term
38. A high relative humidity will:
a. increase evaporative condenser capacity because there is more moisture in the air
b. increase the infiltration load on a refrigeration system
c. increase the time between evaporator defrosts.
d. decrease evaporative condenser capacity because there is less moisture in the air |
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Definition
| b. increase the infiltration load on a refrigeration system 3-10 |
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Term
39. Wet bulb temperatures:
a. require increased evaporative condenser capacity if they are relatively high
b. require increased evaporative condenser capacity if they are relatively low
c. cannot be used to determine the dew point
d. can be determined without using a thermometer. |
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Definition
| a. require increased evaporative condenser capacity if they are relatively high 3-8 |
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Term
40. Cold air:
a. is lighter than warm air.
b. is heavier than warm air
c. holds more moisture than warm air.
d. increases the pressure in a freezer |
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Definition
| b. is heavier than warm air. 3-10 |
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Term
48. Aire with relative humidity of 62% means that
a. the air contains 62% of the water vapor it could hold at the present temp
b. the air can absorb 62% more water vapor at the present temp
c. the air can absorb 38% more water vapor if the temp is reduced
d. the air can absorb 38% more water vapor if the temp is increased |
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Definition
| a. the air contains 62% of the water vapor it could hold at the present temp 3-1 |
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Term
49. If the dry bulb temp is 99F and the RH is 40% what is the vapor pressure of the water vapor in inches Hg?
a. .7
b. .8
c. .65
d. .75 |
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Definition
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Term
50. Dry air is
a. air that has zero moisture content
b. the reciprocal of air density
c. defined by the dry bulb temp
d. a dry bulb condition where the moisture content is below 30% relative humidity |
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Definition
| a. air that has zero moisture content 3-5 |
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Term
51. Higher wet bulb temperatures reduce evaporative condenser capacity because:
a. the dry bulb temp is higher
b. the air has less ability to absorb moisture.
c. the discharge pressure increases
d. the humidity ratio decreases |
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Definition
| b. the air has less ability to absorb moisture 3-8 |
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Term
52. On a psychrometric chart, enthalpy is used to describe
a. the relationship between dry bulb temp and wt bulb temp
b. the specific heat of the air.
c. the relationship of the heat and temp of a substance
d. the total heat content of the dry air and the moisture in the air. |
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Definition
| d. the total heat content of the dry air and the moisture in the air. 3-4 |
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Term
53. The difference between absolute water content in air and relative humidity is
a. relative humidity follows the absolute water content even at subfreezing temps
b. absolute water content stays fixed even if the temp of the air changes
c. relative humidity is measured with a sling psychrometer whereas an electronic meter is used to measure absolute water content.
d. absolute water content will vary as the temp of air changes |
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Definition
| b. absolute water content stays fixed even if the temp of the air changes 3-15 |
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Term
54. at 100% relative humidity
a. the dry bulb temp is lower than the wet bulb temp
b. the dry bulb temp is lower than the dew point temp
c. the dry bulb, wet bulb, and dew point temps are the same
d. evap condensers operate at peak efficiency |
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Definition
| c. the dry bulb, wet bulb, and dew point temps are the same. 3-13 |
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Term
55. At a given dry bulb temp, if the relative humidity increases
a. the wet bulb temp will increase
b. the wet bulb temp will decrease
c. the wet bulb temp is not affected
d. the dry bulb temp also increases |
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Definition
| a. the wet bulb temp will increase 3-13 |
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Term
56. Reducing te evaporating temp of an air unit from 45F to 28F generally causes
a. reduced absolute humidity in the room and higher operating costs
b. increased absolute humidity in the room and lower operating costs.
c. increased moisture condensation on the coil and lower operating costs
d. no changes |
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Definition
| a. reduced absolute humidity in the room and higher operating costs. 3-14 |
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