Psychrometrics definition: degree of saturation / percentage humidity Choose the most accurate definition among the options given. Select the correct statement.
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AThe mass of water vapor present in 1 m³ of dry air.
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BThe mass of water vapor present in 1 kg of dry air.
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CThe ratio of the actual mass of water vapor per kg of dry air to the mass of water vapor per kg of dry air at saturation at the same temperature and pressure.
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DThe ratio of the actual mass of water vapor in a given volume of moist air to the mass of water vapor in the same volume of saturated air at the same temperature and pressure.
Answer
Correct Answer: The ratio of the actual mass of water vapor in a given volume of moist air to the mass of water vapor in the same volume of saturated air at the same temperature and pressure.
Explanation
Concept“Percentage humidity” (often used interchangeably with degree of saturation in basic MCQ contexts) compares actual vapor content to saturated vapor content at the same T and p, on a per volume basis.
Option analysis(A) Absolute humidity (vapor density in a given volume of dry air).(B) Humidity ratio/specific humidity (mass basis per kg dry air).(C) Often used to describe relative humidity in mass-per-mass terms, but the classical “percentage humidity” definition aligns with (D).
Final AnswerThe ratio based on equal volumes at the same T and p — option (D).