Read the following two passages and choose the correct answer for each question.
Various types of fog are essentially clouds that form at the earth's surface, produced by temperature differences and moisture in the air. As warm, moisture-laden air cools, its relative humidity (the amount of moisture that air can contain, which depends on the temperature) increases. Warm air can hold more water vapor than cold air. So if the air is cooled sufficiently it will reach saturation, or the dew point, at which point the moisture begins to condense out of the air and form water droplets, creating fog.
What is the author's main purpose in this passage?
A.To describe various types of fog
B.To explain how fog is formed
C.To define relative humidity
D.To compare the effects of warm air and cold air
Various types of fog are essentially clouds that form at the earth's surface, produced by temperature differences and moisture in the air. As warm, moisture-laden air cools, its relative humidity (the amount of moisture that air can contain, which depends on the temperature) increases. Warm air can hold more water vapor than cold air. So if the air is cooled sufficiently it will reach saturation, or the dew point, at which point the moisture begins to condense out of the air and form water droplets, creating fog.
What is the author's main purpose in this passage?
A.To describe various types of fog
B.To explain how fog is formed
C.To define relative humidity
D.To compare the effects of warm air and cold air
Loga
Hóa Học lớp 12
