With reference to the process of evaporation in the water cycle, consider the following statements: 1. Evaporation of water can take place even in the shade. 2. Water vapour formed during evaporation carries dissolved salts with it into the atmosphere. 3. Warm air can provide the necessary heat for evaporation to occur in shaded areas. Which of the statements given above is/are correct?

Correct Option The correct option is (c) 1 and 3 only. Explanation Evaporation is the physical process by which water changes from a liquid state to a gaseous state (water vapour). This phase transition requires energy, specifically the latent heat of vaporization, to break the bonds holding water molecules together. This energy can be derived from various sources, including direct solar radiation and ambient thermal energy. Statement-wise Analysis - Statement 1 is Correct: Evaporation occurs continuously at temperatures below the boiling point. It does not strictly require direct sunlight. In shaded areas, water absorbs heat energy from the surrounding air and the surface on which it rests, allowing water molecules to gain the kinetic energy necessary to escape into the atmosphere. - Statement 2 is Incorrect: Evaporation acts as a natural distillation process. When water evaporates, only pure water molecules transform into vapour. Dissolved substances, such as salts and minerals, do not evaporate; they remain behind as a residue. This is why water vapour in the atmosphere is fresh, even when it originates from saline oceans. - Statement 3 is Correct: Air possesses thermal energy. In the absence of direct sunlight (shade), warm air acts as the heat source. The heat flows from the warmer air to the cooler water, providing the necessary energy for evaporation to proceed. Key Takeaway: Evaporation is driven by heat energy from any source (sunlight or warm air) and results in the separation of pure water from dissolved impurities like salts.

With reference to the process… - NCERT Class 6 Environment & Ecology MCQ

NCERT Class 6 Environment & Ecology — Chapter 1: Water

mcqmedium

With reference to the process of evaporation in the water cycle, consider the following statements:

Evaporation of water can take place even in the shade.
Water vapour formed during evaporation carries dissolved salts with it into the atmosphere.
Warm air can provide the necessary heat for evaporation to occur in shaded areas.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Science - class 6 · Page 138

Options

A1 and 2 only
B2 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

Correct Option

The correct option is (c) 1 and 3 only.

Explanation

Evaporation is the physical process by which water changes from a liquid state to a gaseous state (water vapour). This phase transition requires energy, specifically the latent heat of vaporization, to break the bonds holding water molecules together. This energy can be derived from various sources, including direct solar radiation and ambient thermal energy.

Statement-wise Analysis

Statement 1 is Correct: Evaporation occurs continuously at temperatures below the boiling point. It does not strictly require direct sunlight. In shaded areas, water absorbs heat energy from the surrounding air and the surface on which it rests, allowing water molecules to gain the kinetic energy necessary to escape into the atmosphere.
Statement 2 is Incorrect: Evaporation acts as a natural distillation process. When water evaporates, only pure water molecules transform into vapour. Dissolved substances, such as salts and minerals, do not evaporate; they remain behind as a residue. This is why water vapour in the atmosphere is fresh, even when it originates from saline oceans.
Statement 3 is Correct: Air possesses thermal energy. In the absence of direct sunlight (shade), warm air acts as the heat source. The heat flows from the warmer air to the cooler water, providing the necessary energy for evaporation to proceed.

Key Takeaway: Evaporation is driven by heat energy from any source (sunlight or warm air) and results in the separation of pure water from dissolved impurities like salts.

Your note

More from Chapter 1: Water

What happens to the water that falls on land as rain and snow? 1. Most of it ultimately flows back to the oceans. 2. None of the rainwater seeps into the ground. 3. It remains permanently on the land surface to form lakes. Select the correct answer using the code given below:

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How does rapid industrialization primarily affect freshwater availability?

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With reference to heavy rains and floods, consider the following statements: 1. Heavy rains can lead to a rise in the water level of rivers and lakes. 2. Floods are generally beneficial for the survival of soil-dwelling animals. 3. Animals living in water can get carried away to land areas during floods and die when water recedes. Which of the statements given above is/are correct?

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What causes the formation of water droplets on the outer surface of a container filled with ice-cold water?

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Which of the following factors contribute to the decreasing availability of usable water? 1. Rising population. 2. Industries consume a negligible amount of water compared to domestic use. 3. Food production requires no water resources. Select the correct answer using the code given below:

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