Worksheet Solutions: Water in the Atmosphere | Geography Class 11 - Humanities/Arts PDF Download

Fill in the Blanks

Q1: Evaporation is caused by an increase in _______________.
Ans: temperature
Evaporation is the process in which a liquid transforms into a gas due to an increase in temperature. As the temperature rises, water molecules gain energy, become more energetic, and transition into a gaseous state.

Q2: Dew forms when the dew point is above the _______________ point.
Ans: freezing
Dew forms on cooler surfaces when the temperature is above freezing, and the air is saturated with moisture, causing condensation to occur.

Q3: Frost forms when the dew point is at or below the _______________ point.
Ans: freezing
Frost forms when the dew point is at or below the freezing point, causing the excess moisture to freeze into ice crystals instead of water droplets.

Q4: The transformation of water vapor into water is called _______________.
Ans: condensation
Condensation is the process in which water vapor turns into a liquid as it loses heat.

Q5: The process of continuous condensation in free air leading to the fall of condensed particles is known as _______________.
Ans: precipitation
Precipitation is the release of moisture in either liquid or solid form when condensation occurs continuously in free air, and the particles become large enough to fall to the Earth's surface.

Q6: Sleet is the result of _______________ air masses with different temperatures.
Ans: layered
Sleet forms when a layer of air with a temperature above freezing point overlies a subfreezing layer near the ground, leading to precipitation in the form of sleet.

Q7: Nimbus clouds are _______________ and form at middle levels.
Ans: black or dark gray
Nimbus clouds are characterized by their dark and opaque appearance, forming at middle levels of the atmosphere.

Q8: Orographic rain occurs when saturated air masses encounter _______________.
Ans: mountains
Orographic rain occurs when moist air is forced to ascend over mountains, leading to condensation and precipitation on the windward side of the mountains.

Q9: As we move from the equator towards the poles, rainfall generally _______________.
Ans: decreases
Rainfall generally decreases as one moves from the equator toward the poles due to changes in climate and atmospheric conditions.

Q10: Seasonal distribution of rainfall is an important aspect in judging its _______________.
Ans: effectiveness
Seasonal distribution of rainfall refers to how rainfall is spread throughout the year, and it is crucial in determining the effectiveness of the rainfall in sustaining ecosystems and agriculture.

Assertion and Reason Based

Q1: Assertion: Evaporation is the process by which water changes from a liquid to a gaseous state.
Reason: Evaporation is caused by the loss of heat.
(a) Both the assertion and reason are true, and the reason is a correct explanation of the assertion.
(b) Both the assertion and reason are true, but the reason is not a correct explanation of the assertion.
(c) Assertion is true, but the reason is false.
(d) Both assertion and reason are false. 
Ans: (b)
Evaporation indeed changes water from a liquid to a gaseous state, and this change is driven by heat. As the water absorbs heat, it transforms into water vapor.

Q2: Assertion: Dew forms on cooler surfaces of solid objects when conditions include clear skies, calm air, and high relative humidity.
Reason: Dew forms when the dew point is below the freezing point.
(a) Both the assertion and reason are true, and the reason is a correct explanation of the assertion.
(b) Both the assertion and reason are true, but the reason is not a correct explanation of the assertion.
(c) Assertion is true, but the reason is false.
(d) Both assertion and reason are false.  
Ans: (b)
The reason explains conditions for dew formation, but the assertion does not require the dew point to be below freezing. Dew forms when surfaces are cooler than the surrounding air.

Q3: Assertion: Fog and mist reduce visibility and can be formed by condensation on fine dust particles in the air.
Reason: Fog and mist are the same phenomenon and have no differences.
(a) Both the assertion and reason are true, and the reason is a correct explanation of the assertion.
(b) Both the assertion and reason are true, but the reason is not a correct explanation of the assertion.
(c) Assertion is true, but the reason is false.
(d) Both assertion and reason are false. 
Ans: (a)
While the reason highlights the role of condensation and dust particles in fog and mist formation, the assertion is correct in stating that fog and mist reduce visibility. Mist has more moisture than fog, making them different.

Q4: Assertion: Clouds are formed by the condensation of water vapor in free air at considerable elevations.
Reason: Clouds always have the same appearance, regardless of their altitude.
(a) Both the assertion and reason are true, and the reason is a correct explanation of the assertion.
(b) Both the assertion and reason are true, but the reason is not a correct explanation of the assertion.
(c) Assertion is true, but the reason is false.
(d) Both assertion and reason are false. 
Ans: (b)
The assertion correctly describes cloud formation due to condensation, but the reason is incorrect. Clouds can have varying appearances based on their altitude and other factors.

Q5: Assertion: Rain shadow areas receive very low rainfall, less than 50 cm per annum.
Reason: Rain shadow areas are typically located on the windward side of mountains.
(a) Both the assertion and reason are true, and the reason is a correct explanation of the assertion.
(b) Both the assertion and reason are true, but the reason is not a correct explanation of the assertion.
(c) Assertion is true, but the reason is false.
(d) Both assertion and reason are false. 
Ans: (a)
The reason correctly explains why rain shadow areas receive low rainfall. They are on the leeward side of mountains, which block moist air, causing low precipitation.

Very Short Answer Type Questions

Q1: Define evaporation.
Ans: Evaporation is the process in which a liquid, such as water, changes into a gaseous state due to an increase in temperature.

Q2: What is the dew point?
Ans: The dew point is the temperature at which air becomes saturated with moisture, leading to condensation.

Q3: How is sleet formed?
Ans: Sleet forms when raindrops encounter colder air below and solidify into small pellets of ice.

Q4: Explain the rain-shadow effect.
Ans: The rain shadow effect occurs when moist air rises over a mountain range, leading to precipitation on the windward side and dry conditions on the leeward side.

Q5: What is the primary factor that causes condensation?
Ans: The loss of heat is the primary factor that causes condensation.

Q6: Name one type of high cloud.
Ans: Cirrus clouds are a type of high cloud.

Q7: What type of clouds are prevalent in areas with warm currents meeting cold currents?
Ans: Cumulonimbus clouds are prevalent in such areas.

Q8: Describe condensation nuclei in relation to fog formation.
Ans: Condensation nuclei are tiny particles, like dust or smoke, around which condensation occurs, leading to fog formation.

Q9: What is the difference between mist and fog?
Ans: Mist contains more moisture than fog. Each nucleus in mist contains a thicker layer of moisture compared to fog.

Q10: What is precipitation, and what forms can it take?
Ans: Precipitation is the release of moisture in either liquid or solid form. It can take the form of rainfall, snowfall, sleet, or hail.

Short Answer Type Questions

Q1: Explain the process of evaporation and its relationship with temperature.
Ans: Evaporation is the transformation of a liquid into a gas, primarily driven by an increase in temperature. When the temperature rises, water molecules gain energy, become more energetic, and transition into a gaseous state.

Q2: Describe the conditions required for the formation of dew and frost.
Ans: Dew forms when the dew point is above the freezing point and requires clear skies, high relative humidity, and cold nights. Frost forms when the dew point is at or below the freezing point.

Q3: How does orographic rain occur, and what is the rain shadow effect?
Ans: Orographic rain occurs when moist air encounters a mountain, is forced to ascend, and cools, leading to condensation and precipitation on the windward side. The rain shadow effect is when the leeward side of the mountain receives less rainfall, creating a dry area known as the rain shadow.

Q4: Differentiate between cirrus and cumulus clouds.
Ans: Cirrus clouds are high-altitude clouds with a feathery appearance, while cumulus clouds look like cotton wool and are formed at lower altitudes in patches.

Q5: Explain the concept of precipitation and provide examples of different forms.
Ans: Precipitation is the release of moisture in either liquid or solid form. Rainfall occurs when the temperature is above freezing, snowfall when it's at or below freezing. Sleet is frozen raindrops, and hail consists of small rounded ice pieces.

Q6: Discuss the three main types of rainfall based on their origin.
Ans: Cyclonic rain is caused by cyclonic activity, convectional rain is due to heated air rising, and orographic rain occurs when moist air masses encounter mountains.

Q7: How does rainfall distribution change as one moves from the equator to the poles?
Ans: Rainfall generally decreases as you move from the equator toward the poles. Coastal areas receive more rainfall than interior regions, and westerly winds affect rainfall distribution in some regions.

Q8: What are the major factors influencing the distribution of rainfall in different parts of the world?
Ans: Factors include proximity to oceans (coastal areas receive more rain), the presence of mountains (orographic rain), and wind patterns (e.g., westerlies).

Long Answer Type Questions

Q1: Explain the processes of evaporation, condensation, and precipitation and their roles in the water cycle.
Ans: The water cycle is a continuous process involving evaporation, condensation, and precipitation. Here's an explanation of each step:

• Evaporation is the transformation of a liquid (e.g., water) into a gas (water vapor) due to an increase in temperature. This process occurs primarily in bodies of water and on the Earth's surface. The heat absorbed from the surroundings energizes water molecules, causing them to become more energetic and transition into a gaseous state.
• Condensation is the opposite process of evaporation, where water vapor changes back into liquid water. This occurs when moist air loses heat, causing water vapor to condense around microscopic particles, forming cloud droplets or dew.
• Precipitation is the release of moisture from the atmosphere to the Earth's surface. It happens when condensation continues in the atmosphere, and the condensed particles grow large enough to fall to the ground. Precipitation can take various forms, including rain, snow, sleet, and hail. It plays a vital role in replenishing Earth's freshwater resources and sustaining ecosystems.

Q2: Describe in detail the formation of fog and mist, their characteristics, and factors influencing their occurrence.
Ans: Clouds play a crucial role in weather patterns. Here are descriptions of various cloud types and their characteristics:

• Cirrus clouds are high-altitude clouds (8,000 - 12,000 meters) with a feathery appearance. They are thin, detached, and always white in color. They often signal fair weather.
• Cumulus clouds resemble cotton wool and are generally found at lower altitudes (4,000 - 7,000 meters). They exist in patches, have a flat base, and can be scattered. They are associated with fair weather but can develop into cumulonimbus clouds during thunderstorms.
• Stratus clouds are layered clouds covering large portions of the sky. They are formed due to factors like heat loss or air mass mixing and often signal overcast conditions.
• Nimbus clouds are black or dark gray, forming at middle levels or near the Earth's surface. They are extremely dense and opaque to sunlight, often causing heavy rainfall and low visibility. Sometimes, they appear to touch the ground. Clouds can take various shapes and forms based on their height, expanse, density, and transparency. They are vital indicators of changing weather conditions.

Q3: Discuss the four types of clouds, their characteristics, and the conditions under which they form.
Ans: Rainfall can be categorized into three primary types based on its origin and the conditions under which it occurs:

• Cyclonic Rain: This type of rainfall is caused by cyclonic activity, such as the convergence of warm and cold air masses along the fronts of cyclones. It results in intense rainfall and stormy weather.
• Convectional Rain: Convectional rainfall occurs when the sun heats the Earth's surface, causing warm air to rise and form convection currents. As the warm air rises, it expands and cools, leading to condensation and the formation of cumulus clouds. This often results in heavy but short-lived rainfall, accompanied by thunder and lightning. Convectional rain is common in equatorial regions and during hot, sunny days.
• Orographic Rain: Orographic rainfall occurs when moist air masses encounter mountain ranges. As the air is forced to ascend over the mountains, it expands, cools, and loses heat, leading to condensation and precipitation. The windward side of the mountains receives significant rainfall, while the leeward side experiences dry conditions, creating a rain shadow effect. Orographic rain is influenced by topography and wind patterns.

Q4: Explain the world distribution of rainfall, focusing on how it varies from the equator to the poles and the major factors influencing this distribution.
Ans: The world distribution of rainfall varies significantly from the equator to the poles due to several influencing factors:

• As one moves away from the equator towards the poles, rainfall generally decreases. Equatorial regions receive heavy rainfall, while polar regions have limited precipitation.
• Coastal areas receive more rainfall than interior regions. This is because oceans are significant sources of moisture, and proximity to water bodies enhances rainfall.
• Rainfall distribution is influenced by the presence of mountains. Orographic rain occurs when moist air masses are forced to ascend over mountain ranges, leading to higher rainfall on the windward side and a rain shadow effect on the leeward side.
• Wind patterns also impact rainfall distribution. For instance, westerlies can bring moisture-laden air to western coastal areas, resulting in increased rainfall.
• Topography, such as the presence of significant mountains, plays a crucial role in influencing local rainfall patterns, creating variations on different sides of the mountains.
• Seasonal distribution of rainfall is an essential aspect to consider. In some regions, rainfall is evenly distributed throughout the year, while in others, it may be more seasonal, with wet and dry periods.