Passage VI
Air at its dew point temperature (or dew point) is saturated with water vapor. Air temperature usually decreases with increasing altitude. When air cools to its dew point, the water vapor in the air can begin to condense and form clouds.
Air temperatures and dew points were measured every 600 m from the surface (0 m) to an altitude of 3,000 m at 4 cities (A-D). Data, including the altitude of the cloud base over each city, were taken at 2 P. M. on every summer day that clouds were present. Figures 1-4 show the average air temperatures, the average dew points, and the average cloud-base altitudes at each city.
35. A certain city reported that the air temperature and the dew point at 0 m altitude measured at 8 A. M. on a given day were both 40°F. Given this information and the data provided, one could be most certain that clouds were present at which of the following altitudes at that city at 8 A.M. on that day?
Your Answer is
Correct Answer is A
Explanation
When the height is 0 m, air temperature=dew point, indicating that there are clouds at this height (actually fog)