With reference to the formation of 'Dew', consider the following statements: 1. It forms when moisture deposits on cold surfaces like stones and grass blades. 2. The ideal conditions include a cloudy sky and strong winds. 3. The dew point must be above the freezing point. Which of the statements given above is/are correct?

The correct option is 1 and 3 only. Explanation Dew is a form of condensation where moisture deposits in the form of water droplets on cooler surfaces of solid objects rather than on nuclei in the air. It occurs when the temperature of the air touching the surface falls below the dew point. Statement-wise Analysis: - Statement 1 is Correct: Dew forms when moisture is deposited on cold surfaces such as stones, grass blades, and plant leaves. This happens because these surfaces lose heat through radiation more rapidly than the surrounding air, causing the air in contact with them to cool and condense its moisture. - Statement 2 is Incorrect: The ideal conditions for the formation of dew are a clear sky, calm air, high relative humidity, and cold, long nights. A cloudy sky prevents the ground from cooling effectively due to the greenhouse effect (clouds trap terrestrial radiation). Strong winds mix the air, preventing the layer immediately in contact with the ground from cooling sufficiently to reach the dew point. - Statement 3 is Correct: For dew to form, the dew point must be above the freezing point. If the dew point is at or below the freezing point, the excess moisture deposits in the form of minute ice crystals, which is known as frost, not dew. Key Takeaway: Dew formation requires clear skies, calm air, and a dew point above freezing (0°C). If the dew point is below freezing, the condensation results in frost.

NCERT Class 11 Geography — Chapter 4: Water in atmosphere

mcqmedium

With reference to the formation of 'Dew', consider the following statements:

It forms when moisture deposits on cold surfaces like stones and grass blades.
The ideal conditions include a cloudy sky and strong winds.
The dew point must be above the freezing point.

Which of the statements given above is/are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A1, 2 and 3
B1 and 3 only
C2 only
D1 and 2 only

Did you get this right?

Solution

The correct option is 1 and 3 only.

Explanation

Dew is a form of condensation where moisture deposits in the form of water droplets on cooler surfaces of solid objects rather than on nuclei in the air. It occurs when the temperature of the air touching the surface falls below the dew point.

Statement-wise Analysis:

Statement 1 is Correct: Dew forms when moisture is deposited on cold surfaces such as stones, grass blades, and plant leaves. This happens because these surfaces lose heat through radiation more rapidly than the surrounding air, causing the air in contact with them to cool and condense its moisture.
Statement 2 is Incorrect: The ideal conditions for the formation of dew are a clear sky, calm air, high relative humidity, and cold, long nights. A cloudy sky prevents the ground from cooling effectively due to the greenhouse effect (clouds trap terrestrial radiation). Strong winds mix the air, preventing the layer immediately in contact with the ground from cooling sufficiently to reach the dew point.
Statement 3 is Correct: For dew to form, the dew point must be above the freezing point. If the dew point is at or below the freezing point, the excess moisture deposits in the form of minute ice crystals, which is known as frost, not dew.

Key Takeaway:
Dew formation requires clear skies, calm air, and a dew point above freezing (0°C). If the dew point is below freezing, the condensation results in frost.

Your note

More from Chapter 4: Water in atmosphere

Which type of rainfall is characterized by a "windward slope" receiving greater rainfall and a "leeward slope" remaining dry?

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In the context of Orographic Rain, the area situated on the leeward side which gets less rainfall is known as:

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In meteorology, the basic classification of clouds into Cirrus, Cumulus, Stratus, and Nimbus is primarily based on which of the following criteria?

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Between latitudes 35° and 40° N and S of the equator, the rainfall is generally heavier on which margin of the continents?

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Which of the following best explains why rainfall is first received on the western margins of continents between 45° and 65° N and S latitudes?

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The correct option is 1 and 3 only.

Explanation

Statement-wise Analysis:

Statement 1 is Correct: Dew forms when moisture is deposited on cold surfaces such as stones, grass blades, and plant leaves. This happens because these surfaces lose heat through radiation more rapidly than the surrounding air, causing the air in contact with them to cool and condense its moisture.
Statement 2 is Incorrect: The ideal conditions for the formation of dew are a clear sky, calm air, high relative humidity, and cold, long nights. A cloudy sky prevents the ground from cooling effectively due to the greenhouse effect (clouds trap terrestrial radiation). Strong winds mix the air, preventing the layer immediately in contact with the ground from cooling sufficiently to reach the dew point.
Statement 3 is Correct: For dew to form, the dew point must be above the freezing point. If the dew point is at or below the freezing point, the excess moisture deposits in the form of minute ice crystals, which is known as frost, not dew.

Key Takeaway:
Dew formation requires clear skies, calm air, and a dew point above freezing (0°C). If the dew point is below freezing, the condensation results in frost.