Under what conditions does the evaporation rate from a water surface accelerate_________________?
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Answer: A. difference of vapour pressure between water and air is increased
Explanation
Evaporation rate increases when the vapor pressure gradient between the water surface and surrounding air grows. A larger difference in vapor pressure accelerates molecular diffusion of water vapor into the atmosphere. Dalton law of evaporation confirms that mass transfer is directly proportional to this vapor pressure deficit. Vapor pressure at the water surface depends strictly on water temperature, while ambient air pressure varies. Wind velocity helps maintain this vapor pressure gradient by sweeping away humid air above the water surface. Solar radiation supplies the necessary latent heat of vaporization required for phase change to occur.
Option B is wrong because decreasing wind velocity reduces vapor removal and slows down evaporation rates. Option C is incorrect since decreasing soluble solids slightly increases vapor pressure but does not drive the main gradient. Option D is invalid because vapor pressure differences fundamentally govern the rate of surface evaporation.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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