Maharashtra Board Class 8 Geography Chapter 3 Humidity and Clouds Solutions

Class 8 Geography Chapter 3 Humidity And Clouds Textbook Questions And Answers

Question 1. Match the column and complete the chain:

'A' Column	'B' Column	'C' Column
1. Cirrus	i. Vertical extent in the sky	a. Roaring clouds
2. Cumulonimbus	ii. Higher altitude	b. Floating clouds
3. Nimbostratus	iii. Medium altitude	c. Continuous rainfall
4. Alto-cumulus	iv Low altitude	d. Snowflake clouds

Answer:

'A' Column	'B' Column	'C' Column
1. Cirrus	ii. Higher altitude	d. Snowflake clouds
2. Cumulonimbus	i. Vertical extent in the sky	a. Roaring clouds
3. Nimbostratus	iv Low altitude	c. Continuous rainfall
4. Alto-cumulus	iii. Medium altitude	b. Floating clouds

In simple words: This question tests your ability to associate different cloud types with their characteristics (altitude, vertical extent) and associated weather phenomena. Matching columns helps organize these relationships.

🎯 Exam Tip: Understanding cloud types and their characteristics is crucial. Focus on altitude classifications (high, medium, low) and the weather events they typically indicate for higher scores.

Question 2. Choose the correct word from the brackets and complete the sentences:(Options: Cumulonimbus, relative humidity, absolute humidity, condensation, vapor-holding capacity)
Question a. The ............ of the air is dependent on the temperature of the air.
Answer: vapour-holding capacity
In simple words: Air's capacity to hold moisture changes with temperature; warmer air can hold more water vapor.

🎯 Exam Tip: Pay attention to keywords like "dependent on temperature" to correctly identify the relevant humidity concept. Precision in definitions is key.

Question b. The amount of vapour in 1 cu.m, of air shows the ............
Answer: absolute humidity
In simple words: Absolute humidity directly measures the total amount of water vapor in a specific volume of air.

🎯 Exam Tip: Distinguish between absolute humidity (actual amount) and relative humidity (percentage of saturation) in your answers. Units like "gms/cu.m." are indicators of absolute humidity.

Question c. As ............. is less in the desert areas, the air is dry there.
Answer: relative humidity
In simple words: Deserts are dry because the air's relative humidity is very low, meaning it's far from being saturated with moisture.

🎯 Exam Tip: Connect environmental conditions (desert) with the appropriate humidity type (relative humidity). Low relative humidity implies dry air, even if absolute humidity is present.

Question d. ............. type of clouds are indicators of the storm.
Answer: Cumulonimbus
In simple words: Cumulonimbus clouds are tall, dark clouds that signal severe weather like thunderstorms and heavy rain.

🎯 Exam Tip: Memorize the specific cloud types associated with different weather conditions (e.g., Nimbostratus for continuous rain, Cumulonimbus for storms) for quick recall.

Question e. In a free environment, the ............. of the vapour present in the atmosphere takes place around the dust particles.
Answer: condensation
In simple words: Water vapor in the air turns into liquid water droplets or ice crystals around tiny dust particles, forming clouds or dew.

🎯 Exam Tip: Understand the role of condensation nuclei (dust particles) in the process of condensation, which is fundamental to cloud formation and precipitation.

Question 3. Differentiate between:
Question a. Humidity and clouds:
Answer:

Humidity	Meaning	Clouds
The amount of water vapour present in the air is called humidity.	A mass of fine particles of ice and water accumulated around the dust particles in the air at high altitude is called a cloud.
Visibility
Humidity is in the invisible form.	Clouds are in the visible form.

In simple words: Humidity is the invisible water vapor in the air, while clouds are visible masses of tiny water droplets or ice crystals formed by condensed humidity at high altitudes.

🎯 Exam Tip: When differentiating, clearly state definitions and key distinguishing characteristics (e.g., visibility, composition, altitude). Use a tabular format if possible to present differences clearly.

Question b. Relative humidity and Absolute humidity
Answer:

Relative humidity	Absolute humidity
Meaning
The amount of water vapour present in air expressed as a percentage of the amount needed for saturation at the same temperature is called relative humidity.	The amount of water vapour in 1 cu.m. of air is called the absolute humidity.
Formula
\( \text{Relative humidity (\%)} = \frac{\text{Absolute humidity}}{\text{Vapour-holding capacity}} \times 100 \)	\( \text{Absolute humidity} = \frac{\text{Mass of water vapour}}{\text{Volume of air}} \)

In simple words: Absolute humidity is the actual amount of water vapor in a specific volume of air, while relative humidity is the percentage of moisture the air holds compared to its maximum capacity at that temperature.

🎯 Exam Tip: Understand both the definitions and the formulas for relative and absolute humidity. Practice applying these formulas to numerical problems for a complete understanding.

Question c. Cumulus clouds and Cumulonimbus clouds
Answer:

Cumulus clouds	Cumulonimbus clouds
Meaning
The clouds that are found from 500 m to 6000 m altitude having comparatively less vertical expanse are called cumulus clouds.	The clouds that are found from 500 m to 6000 m altitude having comparatively more vertical expanse are called cumulonimbus clouds.
Meaning
Cumulus clouds are the indicators of pleasant weather.	Cumulonimbus clouds are the indicators of thunderstorm.

In simple words: Cumulus clouds are fluffy, fair-weather clouds with limited vertical growth, whereas Cumulonimbus clouds are massive, vertically developed clouds that bring thunderstorms and heavy rain.

🎯 Exam Tip: Focus on the vertical development and the associated weather types to distinguish between Cumulus and Cumulonimbus clouds. Visualizing their shapes can also help in remembering their characteristics.

Question 4. Answer the following questions:
Question a. Why is the air in a region dry?
Answer: Due to the low amount of the moisture in the air, the air in a region is dry.
In simple words: Air is dry when it contains very little water vapor, which means it has a low level of humidity.

🎯 Exam Tip: This is a straightforward definition. Ensure you clearly state the inverse relationship between moisture content and dryness for full marks.

Question b. How is humidity measured?
Answer:
1. The amount of water vapour in 1 cu.m, of air is called the absolute humidity.
2. Absolute humidity is measured with the help the following formula:
\[ \text{Absolute humidity} = \frac{\text{Mass of water vapour}}{\text{Volume of air}} \]
3. The amount of water vapour present in air expressed as a percentage of the amount needed for saturation at the same temperature is called relative humidity.
4. Relative humidity is measured with the help of the following formula:
\[ \text{Relative humidity (\%)} = \frac{\text{Absolute humidity}}{\text{Vapour-holding capacity}} \times 100 \]
In simple words: Humidity is measured as absolute humidity (actual water vapor per cubic meter) or relative humidity (percentage of water vapor compared to maximum capacity), each using specific formulas.

🎯 Exam Tip: Provide both types of humidity (absolute and relative) and their respective formulas for a comprehensive answer. Clearly state the units where applicable.

Question c. What are the prerequisites for condensation?
Answer: High relative humidity and dew point temperature of the air are the prerequisites for condensation.
In simple words: For water vapor to condense, the air needs to be nearly saturated with moisture (high relative humidity) and cool down to its dew point.

🎯 Exam Tip: Highlight both "high relative humidity" and "dew point temperature" as these are the two critical conditions for condensation to occur. Understanding dew point is crucial.

Question d. What is a cloud? Write its types.
Answer:
A. Meaning:
A visible mass of fine particles of ice and water accumulated around the dust particles in the air at high altitude is called a cloud.
B. Types:
The following are the types of clouds:
1. High clouds: Clouds at an altitude of 7000 m to 14000 m are considered as high clouds. Cirrus, Cirro-Stratus and Cirro-Cumulus are high clouds.
2. Medium clouds: Clouds at an altitude of 2000 m to 7000 m are considered as medium clouds. Alto-Stratus and Alto-Cumulus are medium clouds.
3. Low clouds: Clouds at an altitude of less than 2000m are considered as low clouds. Strato-Cumulus, Stratus, Nimbostratus, Cumulus and Cumulonimbus are low clouds
In simple words: A cloud is a visible collection of tiny water droplets or ice crystals suspended in the atmosphere, categorized by their altitude as high, medium, or low clouds.

🎯 Exam Tip: Define a cloud accurately and then provide a clear, categorized list of cloud types based on altitude, mentioning examples for each category. Accuracy in altitude ranges is important.

Question e. Which type of clouds give rain?
Answer: Nimbostratus and cumulonimbus type of clouds give rain.
In simple words: Nimbostratus clouds bring steady, continuous rain, while Cumulonimbus clouds are responsible for heavy showers and thunderstorms.

🎯 Exam Tip: Specifically name the two primary rain-bearing cloud types. Understanding their distinct precipitation patterns (continuous vs. heavy/stormy) adds value to the answer.

Question f. On what does the percentage of relative humidity depend?
Answer: The percentage of relative humidity depends on the absolute humidity and vapour-holding capacity of the air at a given temperature.
In simple words: Relative humidity is determined by how much moisture is actually in the air (absolute humidity) compared to how much it can hold (vapor-holding capacity) at its current temperature.

🎯 Exam Tip: Recall the formula for relative humidity to easily remember its two direct dependencies: absolute humidity and vapor-holding capacity (which is temperature-dependent).

Question 5. Give geographical reasons for the following:
Question a. Clouds float in the sky.
Answer:
1. The condensed water or fine particles of snow accumulate around dust particles at high altitudes leading to formation of clouds.
2. The condensed water or fine particles in the clouds are almost weightless. Therefore, clouds float in the sky.
In simple words: Clouds float because they are made of tiny, lightweight water droplets or ice crystals that are so small they remain suspended in the air, overcoming gravity.

🎯 Exam Tip: Emphasize the "fine particles" and "almost weightless" aspects. Also, mention the role of updrafts and atmospheric buoyancy, though not explicitly in the given answer, it enhances understanding.

Question b. The proportion of relative humidity changes according to altitude.
Answer:
1. The temperature is found to be comparatively high in the areas at sea level. Due to high temperature, moisture-holding capacity of air near sea level is found to be high. Therefore, the humidity of the air at sea level is comparatively high.
2. The temperature is found to be comparatively low in the areas at high altitude. Due to low temperature, moisture-holding capacity of air at high altitudes is found to be low. Therefore, the humidity of the air at high altitude is comparatively low. In this way, the proportion of relative humidity changes according to the altitude.
In simple words: Relative humidity changes with altitude because temperature decreases with height, which affects the air's capacity to hold moisture.

🎯 Exam Tip: Clearly link the change in temperature with altitude to the air's moisture-holding capacity, and then to the resulting relative humidity variations. Use comparative language (high vs. low) effectively.

Question c. Air becomes saturated.
Answer:
1. At certain temperature, the moisture-holding capacity of air gets fulfilled and it becomes equal to the proportion of the moisture present in it.
2. At this state, no more moisture can be absorbed by the air. Thus, air becomes saturated.
In simple words: Air becomes saturated when it holds the maximum amount of water vapor possible at its current temperature, unable to absorb any more moisture.

🎯 Exam Tip: Focus on the concept of "maximum capacity" and the equality between moisture present and moisture-holding capacity. This is a fundamental concept in humidity and weather.

Question d. Cumulus clouds change into cumulonimbus clouds.
Answer:
1. Cumulus clouds are found between 500 m to 6000 m altitude. They are mostly formed due to the vertical flow of the air.
2. Sometimes, the vertical expanse of the cumulus clouds increases and it leads to formation of huge mountain-like cumulonimbus clouds. Thus, cumulus clouds change into cumulonimbus clouds.
In simple words: Cumulus clouds can grow into cumulonimbus clouds when strong vertical air currents cause them to expand significantly upwards, becoming large, storm-producing formations.

🎯 Exam Tip: Emphasize the "vertical flow of air" and "vertical expanse" as the key mechanisms for the transformation from cumulus to cumulonimbus clouds. Mention the "mountain-like" appearance.

Question 6. Solve the following:
Question a. When the temperature of the air is 30° C, its vapour-holding capacity is 30.37 gms/cu.m., If absolute humidity is 18 gms/cu.m., then what will be the relative humidity?
Answer:
Relative humidity (%)
\[ = \frac{\text{Absolute humidity}}{\text{Vapour-holding capacity}} \times 100 \]
\[ = \frac{18.00}{30.37} \times 100 \]
\[ = 59.26 \% \]
In simple words: To find relative humidity, divide the actual moisture in the air (absolute humidity) by the maximum moisture it can hold (vapor-holding capacity) at that temperature, then multiply by 100 to get a percentage.

🎯 Exam Tip: Clearly write down the formula first, substitute the given values correctly, and perform the calculation accurately. Always include the unit (%) for relative humidity in the final answer.

Question b. What would be the absolute humidity of air if 1 cu.m, air contains 4.08 gms of vapour at 0° C temperature.
Answer:
Absolute humidity
\[ = \frac{\text{Mass of water vapour}}{\text{Volume of air}} \]
\[ = \frac{4.08}{1} \]
\[ = 4.08 \text{ gm/m}^3 \]
In simple words: Absolute humidity is simply the mass of water vapor divided by the volume of air it occupies, giving the concentration of moisture.

🎯 Exam Tip: Remember the definition of absolute humidity is the mass of water vapor per unit volume of air. Ensure units are correctly stated in the final answer (e.g., gm/m³ or gm/cu.m.).

Question 7. Collect the weather related information from newspapers for the month of July. Relate the difference in the maximum and minimum temperatures with humidity.
Answer: This is an activity-based question that requires practical observation and data collection. Students should collect daily weather data for July, noting maximum and minimum temperatures and humidity levels. They should then analyze how a larger difference between max and min temperatures (a higher diurnal range) typically correlates with lower humidity (especially in drier climates), while a smaller difference (lower diurnal range) often correlates with higher humidity, as water vapor traps heat and reduces temperature fluctuations.
In simple words: This activity asks you to observe how daily temperature swings in July relate to how much moisture is in the air. Big temperature differences often mean drier air, while smaller differences can mean more humid air.

🎯 Exam Tip: For activity-based questions, describe the process of data collection and the expected observations or conclusions. Emphasize analytical skills and relating real-world data to geographical concepts.

Activity:

Question a. Make a table showing the types of clouds. Use various photographs.
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र बादलों के विभिन्न प्रकारों को उनकी ऊँचाई के अनुसार वर्गीकृत करता है। इसमें निचले स्तर (2000 मीटर से कम), मध्यम स्तर (2000-7000 मीटर) और उच्च स्तर (7000-14000 मीटर) के बादलों को उनके विशिष्ट आकार और स्थान के साथ दर्शाया गया है, जिससे छात्र विभिन्न बादल संरचनाओं की पहचान कर सकें।
Answer:

No.	Types of Clouds	General Altitude (meters)
1.	Cirrus	7000 to 14000
2.	Cirro-Stratus
3.	Cirro-Cumulus
4.	Alto-Stratus	2000 to 7000
5.	Alto-Cumulus
6.	Strato-Cumulus	Less Than 2000
7.	Stratus
8.	Nimbostratus
9.	Cumulus	The extent could be variable
10.	Cumulonimbus

In simple words: This question asks you to create a table classifying clouds by their types and general altitudes, as typically shown in geography textbooks, often accompanied by visual examples.

🎯 Exam Tip: When presenting cloud types, always categorize them by altitude (high, medium, low). Including examples for each category and understanding their visual characteristics is essential.

Class 8 Geography Chapter 3 Humidity And Clouds Additional Important Questions And Answers

Examine the following statements and correct the incorrect ones:
Question a. Cumulonimbus clouds are the indicators of the pleasant atmosphere.
Answer:
Incorrect.
Correct statement: Cumulonimbus clouds are the indicators of the thunderstorm.
In simple words: Cumulonimbus clouds signal stormy weather, not pleasant conditions, because they are associated with heavy rain, thunder, and lightning.

🎯 Exam Tip: Be precise with the weather conditions associated with specific cloud types. Answering "Incorrect" is not enough; always provide the correct statement or reason.

Question b. The relative humidity is found to be high in desert region.
Answer:
Incorrect.
Correct statement: The relative humidity is found to be less in desert region.
In simple words: Deserts have low relative humidity, not high, because there's very little moisture in the air compared to what it could hold.

🎯 Exam Tip: Understand the environmental factors that influence humidity. Deserts are defined by aridity, which directly implies low relative humidity. Focus on the core geographical principles.

Question c. The high temperature of the air leads to rapid evaporation.
Answer:
Correct.
In simple words: Warmer air increases the rate at which water turns into vapor, leading to faster evaporation.

🎯 Exam Tip: Recognize the direct relationship between temperature and evaporation rate. Higher energy (heat) allows water molecules to escape into the atmosphere more easily.

Question d. When the humidity in the air is 0 gm/cu.m. at any temperature, the air is said to be humid.
Answer:
Incorrect.
Correct statement: When the humidity in the air is 0 gm/cu.m. at any temperature, the air is said to be dry.
In simple words: Air with zero absolute humidity means it contains no water vapor at all, making it completely dry, not humid.

🎯 Exam Tip: A value of "0 gm/cu.m." for humidity signifies the complete absence of moisture, which by definition means the air is dry. Be precise with terminology.

Question e. Cirrostratus appears like a bed sheet with wrinkles.
Answer:
Correct.
In simple words: Cirrostratus clouds form a thin, sheet-like layer that often covers the sky, sometimes showing a slightly wrinkled appearance.

🎯 Exam Tip: Visual descriptions of clouds are important. Associate specific cloud types with their unique appearances for better recall and identification.

Answer the following questions in one sentence each:
Question a. What is evaporation?
Answer: The process of converting water into steam or water vapour is called evaporation.
In simple words: Evaporation is when liquid water changes into a gaseous state (water vapor) and rises into the atmosphere.

🎯 Exam Tip: Provide a concise and accurate definition, focusing on the change of state from liquid to gas. Mentioning the role of heat can also be beneficial.

Question b. What is meant by the moisture-holding capacity of air?
Answer: The capacity of air to hold moisture at a given temperature, is called the moisture-holding capacity of air.
In simple words: Moisture-holding capacity is the maximum amount of water vapor that a volume of air can contain at a specific temperature.

🎯 Exam Tip: Emphasize that moisture-holding capacity is temperature-dependent and represents the *maximum* amount of vapor air can hold. This is crucial for understanding saturation.

Question c. What is meant by the saturation of the air?
Answer: The condition of air at a certain temperature, in which the moisture-holding capacity of air becomes equal to the proportion of moisture present in it, is called saturation of the air.
In simple words: Air is saturated when it has absorbed all the water vapor it possibly can at its current temperature, meaning its relative humidity is 100%.

🎯 Exam Tip: Define saturation by linking it to the point where the air's actual moisture content equals its maximum moisture-holding capacity at a specific temperature.

Answer the following questions in brief:
Question a. Write in brief about the features of high clouds.
Answer: Clouds at an altitude of 7000 m to 14000 m are considered as high clouds. High clouds are mainly made up of ice particles. Cirrus, Cirro-Stratus and Cirro-Cumulus are high clouds. The following are the features of high clouds :
1. Cirrus: Cirrus are wispy.
2. Cirro-Stratus: Cirro-Stratus look like bed sheet with wrinkles. A halo is generally seen around these clouds.
3. Cirro-Cumulus clouds: Cirro-Cumulus look like groups of small waves.
In simple words: High clouds, found at altitudes of 7,000-14,000 meters, are made of ice crystals and include wispy Cirrus, sheet-like Cirro-Stratus, and wavy Cirro-Cumulus clouds.

🎯 Exam Tip: Remember the altitude range (7000-14000m) and composition (ice particles) for high clouds. Also, memorize distinct visual characteristics for each type (wispy, sheet-like, wavy).

Question b. Write in brief about the features of medium clouds.
Answer: Clouds at an altitude of 2000 m to 7000 m are considered as medium clouds. Alto-Stratus and Alto-Cumulus are medium clouds. The following are the features of medium clouds :
1. Alto-Stratus: Alto-Stratus are comparatively thin. The sun is visible through these clouds as if seen through a milky glass.
2. Alto-Cumulus: Alto-Cumulus are in the form of layers. They have wave-like structure. They are white in colour and have a grey shade.
In simple words: Medium clouds, located at 2,000-7,000 meters, consist of Alto-Stratus (thin, milky) and Alto-Cumulus (layered, wavy, white to grey) types.

🎯 Exam Tip: For medium clouds, note the altitude range (2000-7000m) and the common prefixes "Alto-". Describe the key visual characteristics of Alto-Stratus (translucent) and Alto-Cumulus (wavy layers).

Question c. Write in brief about the features of Strato-Cumulus, Stratus and Nimbostratus.
Answer: The features of Strato-Cumulus, Stratus and Nimbostratus are as follows :
1. Strato-Cumulus: Strato-Cumulus have layers. These clouds are mostly seen in round clusters. They are white to earthy in colour.
2. Stratus: Stratus are found in layers. They have uniform base. They are ash coloured.
3. Nimbostratus: Nimbostratus have thick layers. They are greyish in colour. They cause continuous rainfall. They are also responsible for snowfall.
In simple words: Strato-Cumulus clouds are layered, round clusters; Stratus clouds are uniform, ash-colored layers; and Nimbostratus clouds are thick, grey layers bringing continuous rain or snow.

🎯 Exam Tip: When describing these low clouds, focus on their layered appearance (strato- prefix) and specific features: Strato-Cumulus (clusters), Stratus (uniform base), and Nimbostratus (rain-bearing).

Question d. Write in brief about the features of Cumulus and Cumulonimbus.
Answer: The features of Cumulus and Cumulonimbus are as follows :
1. Cumulus: Cumulus are found between 500 m to 6000 m altitude. They are mostly formed due to the vertical flow of the air. They have huge size and dome-like shape. They are grey in colour. They indicate pleasant atmosphere. With an increase in the vertical expanse, these clouds turn into cumulonimbus clouds and bring rain.
2. Cumulonimbus: Cumulonimbus appear like huge mountain. They are dense and dark in colour. They have anvil-like shape at the top. They are the indicators of thunder, lightning and storm. They bring rain with storm. Sometimes they also bring hailstones. The raindrops of these clouds are found to be larger in size.
In simple words: Cumulus clouds are dome-shaped, fair-weather clouds that can grow vertically into massive, storm-producing Cumulonimbus clouds, known for their anvil tops and severe weather.

🎯 Exam Tip: Differentiate these two by their vertical development and associated weather. Cumulus indicates fair weather, while Cumulonimbus is synonymous with thunderstorms, lightning, and large raindrops.

Give geographical reasons for the following:
Question a. The absolute humidity of air in coastal region is higher than humidity of air in inland areas.
Answer:
1. The rate of evaporation is found to be high in the coastal region. As its effect, the amount of moisture in air in coastal region is found to be high. This results in high absolute humidity of air in coastal region.
2. On the other hand, the rate of evaporation is found to be low in the inland areas. As its effect, the amount of moisture in air in inland regions is found to be low. This results in low absolute humidity of air in inland areas. Thus, the absolute humidity of air in coastal region is higher than humidity of air in inland areas.
In simple words: Coastal areas have higher absolute humidity due to abundant water bodies (oceans, seas) leading to increased evaporation, while inland areas, lacking large water sources, experience less evaporation and thus lower absolute humidity.

🎯 Exam Tip: When explaining geographical reasons, always identify the primary factor (e.g., proximity to water bodies for coasts, absence for inland) and explain its causal link to the observed phenomenon (evaporation rate, moisture content, absolute humidity).

Question b. The absolute humidity of air in equatorial region is higher than humidity of air in polar region.
Answer:
1. Equatorial region receives perpendicular sunrays throughout the year leading to high temperature. High temperature increases the rate of evaporation and this further leads to high absolute humidity of air in equatorial region.
2. Polar regions receive extremely slanted sunrays throughout the year leading to very low temperature. Very low temperature decreases the rate of evaporation and this further leads to very low absolute humidity of air in polar region. Thus, the absolute humidity of air in equatorial region is higher than humidity of air in polar region.
In simple words: Equatorial regions are hotter and have more evaporation, leading to high absolute humidity, while polar regions are very cold with minimal evaporation, resulting in low absolute humidity.

🎯 Exam Tip: Link the intensity of sunrays and resulting temperature directly to the rate of evaporation and, consequently, absolute humidity. Compare and contrast the two regions to highlight the differences clearly.

Question c. Damp air is found in the coastal regions.
Answer:
1. The rate of evaporation is found to be high in the coastal region. As its effect, the amount of moisture in air in coastal region is found to be high.
2. The absolute humidity of the air near coastal region is found to be high. Therefore, damp air is found in the coastal regions.
In simple words: Coastal regions have damp air because the proximity to large water bodies causes high evaporation, increasing the moisture content and absolute humidity in the atmosphere.

🎯 Exam Tip: Explain the direct chain of cause and effect: presence of water -> high evaporation -> high moisture content -> high absolute humidity -> damp air. This shows a complete understanding of the concept.

Question d. Dry air is found in the inland regions.
Answer:
1. The rate of evaporation is found to be low in inland region. As its effect, the amount of moisture in air in inland region is found to be low.
2. The absolute humidity of the air in inland region is found to be low. Therefore, dry air is found in inland regions.
In simple words: Inland regions have dry air because they are far from large water sources, resulting in less evaporation and thus lower moisture content in the atmosphere.

🎯 Exam Tip: Contrast with coastal regions; emphasize the lack of large water bodies as the primary reason for low evaporation, leading to low moisture content and dry air in inland areas.

Differentiate between the following:
Question a. Densification and Sublimation :
Answer:

Densification	Sublimation
Meaning
The process of changing of water vapour in the air into liquid state, i.e. water is called densification.	The process of changing water vapour in the air into solid state, i.e. snow is called sublimation.
Outcome
Densification leads to precipitation on the surface of the earth.	Sublimation leads to snowfall on the surface of the earth.

In simple words: Densification is water vapor changing into liquid water, often causing rain, while sublimation is water vapor directly changing into solid ice (like snow), skipping the liquid phase.

🎯 Exam Tip: Clearly define each term as a phase change (vapor to liquid vs. vapor to solid) and specify the resulting precipitation type (rain vs. snow). Understanding the states of matter is key.

Study the following map/figure /graph and answer the following questions:
Question 1. Study the figure 3.7 given on page 20 of the textbook and answer the following questions:
Question a. What is the maximum diameter of the raindrop?
Answer: The maximum diameter of the raindrop is 5 mm.
In simple words: Based on the textbook figure, the largest size a raindrop can typically reach is 5 millimeters in diameter.

🎯 Exam Tip: For figure-based questions, accurately extract the specific data point requested from the provided visual. Double-check units and values to avoid errors.

Question b. Around what does the condensation of the water vapour in the air occur?

Answer: The condensation of the water vapour in the air occurs around the minute particles of dust or salt in the air.
In simple words: Water vapor condenses onto tiny airborne particles like dust or salt to form liquid water droplets.

🎯 Exam Tip: Understanding the role of condensation nuclei (dust, salt particles) is crucial for explaining cloud formation.

Question 2. Study the Figure 3.9 given on page 22 of the textbook and answer the following questions:

Question a. Which type of charge is found at the upper end of the cumulonimbus clouds?

Answer: Positive charge is found at the upper end of the cumulonimbus clouds.
In simple words: The top part of cumulonimbus clouds typically carries a positive electrical charge.

🎯 Exam Tip: Remember the charge distribution in cumulonimbus clouds (positive at top, negative at bottom) as it's key to understanding lightning.

Question b. Which type of charge is found at the low end of the cumulonimbus clouds?

Answer: Negative charge is found at the low end of the cumulonimbus clouds.
In simple words: The bottom part of cumulonimbus clouds usually has a negative electrical charge.

🎯 Exam Tip: Knowing the charge at the base of these clouds helps explain why lightning often strikes from cloud to ground.

Question c. Which type of charge is found on the land below the cumulonimbus clouds?

Answer: Positive charge is found on the land below the cumulonimbus clouds.
In simple words: The ground directly under a cumulonimbus cloud becomes positively charged due to induction from the negatively charged cloud base.

🎯 Exam Tip: The induced positive charge on the ground is essential for the formation of cloud-to-ground lightning bolts.

Use Your Brainpower!

Question a. Find where the symbols given below are used while showing the weather of a place. Write their meanings in the boxes given below:

Answer:

ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक स्पष्ट आकाश और एक चमकते सूरज को दर्शाता है, जो किसी भी बादल या वर्षा की अनुपस्थिति का संकेत देता है। Clear Sky, No chance of rain.	ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक आंशिक रूप से बादल वाले आकाश को दर्शाता है, जिसमें सूरज बादलों के पीछे छिपा हुआ है, जो हल्की वर्षा की संभावना का सुझाव देता है। Moderately cloudy sky, Chance of light rain.	ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र भारी, गहरे बादलों वाले आकाश को दर्शाता है, जिसमें से वर्षा की बूंदें गिर रही हैं, जो भारी वर्षा की संभावना का स्पष्ट संकेत है। Cloudy sky, Chance of heavy rain.

In simple words: These symbols are used in weather forecasts to quickly communicate sky conditions and the likelihood of rain.

🎯 Exam Tip: Knowing common weather symbols is practical for daily life and can be asked in short observational questions.

Thought-Provoking Questions:

Think About It.

Question a. During winters, when you exhale on the glass of your mirror, what happens. If you do this in summer why doesn't it happen?

Answer:
1. During winters, the moisture-holding capacity of air is low due to low temperature. Therefore during winters, when we exhale on the glass of mirror, the condensation of water vapour present in the exhaled air takes place. As its effect very thin water drops are found on the glass of mirror.
2. During summer, the moisture-holding capacity of air is high due to high temperature. Therefore during summer, when we exhale on the glass of mirror, the water vapour present in the exhaled air gets absorbed in air. Therefore, no water drops are found on the glass of mirror.
In simple words: In winter, the cold mirror surface causes water vapor from your breath to condense into tiny droplets, making the glass foggy. In summer, the mirror is warmer, so the water vapor doesn't condense but rather mixes with the air.

🎯 Exam Tip: This question tests your understanding of temperature's effect on air's moisture-holding capacity and the process of condensation.

Give It A Try.

The vapour-holding capacity of 1 cu.m, of air in various temperature is given in the following table.

Calculate the difference in the capacities by observing the following table:

(Note: The answer is given directly.)

Question a.

Temperature of the air( 0 C)	Vapour holding capacity (gm/cu.m.)	Difference in the capacities (gm/cu.m)
-5	3.26	-
0	4.85	1.59
5	6.80
10	9.40
15	12.83
20	17.30
30	30.37
40	51.12

Answer:

Temperature of the air (°C)	Vapour-holding (gm/cu.m³)capacity	Difference in the capacities (gm/cu.m³)
-5	3.26	-
0	4.85	1.59
5	6.80	1.95
10	9.40	2.60
15	12.83	3.43
20	17.30	4.47
30	30.37	13.07
40	51.12	20.75

In simple words: The table illustrates that as temperature increases, the air's capacity to hold water vapor significantly rises, leading to larger differences in capacity at higher temperature intervals.

🎯 Exam Tip: Pay attention to how the difference in vapor-holding capacity changes with increasing temperature; this demonstrates the non-linear relationship between temperature and humidity.

Use Your Brain Power!

Question a. In which season is humidity generally more?

Answer: Humidity is generally more in monsoon.
In simple words: Humidity is typically higher during the monsoon season due to increased evaporation and rainfall.

🎯 Exam Tip: Relate seasonal changes to geographical factors like rainfall and temperature to explain variations in humidity.

Question b. How does the humidity affect the human body?

Answer: The rate of respiration and sweating increases due to humidity.
In simple words: High humidity makes it harder for sweat to evaporate, reducing the body's cooling efficiency and increasing both sweating and breathing rates to regulate temperature.

🎯 Exam Tip: Focus on the body's thermoregulation process and how humidity interferes with it, leading to discomfort.

Question c. Observe how humidity affects the food materials at our home and write about the same.

Answer: Due to humidity, fungus flourish on food materials at our home and it gets spoiled.
In simple words: High humidity creates a moist environment that promotes the rapid growth of mold and fungi, causing food to spoil quickly.

🎯 Exam Tip: This is a practical application question; highlight the role of moisture in microbial growth and food spoilage.

Question d. Is there any relationship between formation of fungus and humidity?

Answer: There is a direct relationship between formation of fungus and humidity. Humidity supports the growth of fungus.
In simple words: Yes, high humidity directly favors the growth of fungus because fungi thrive in moist conditions.

🎯 Exam Tip: Emphasize the direct correlation; humidity provides the necessary moisture for fungal proliferation.

Question e. How is the early or late drying up of clothes related to humidity?

Answer: As the moisture-holding capacity is found to be high in low humidity air, it leads to early drying up of clothes. As the moisture-holding capacity is found to be low in high humidity air, it leads to late drying up of clothes.
In simple words: Clothes dry faster in low humidity because the air can absorb more moisture from the clothes. Conversely, in high humidity, the air is already saturated with moisture, slowing down the evaporation from clothes, causing them to dry slowly.

🎯 Exam Tip: This question assesses your understanding of evaporation rates and the air's moisture-holding capacity in relation to humidity.

Think About It.

Question a. What will happen if the temperature of saturated air at 20° C drops to 10° C abruptly?

Answer:
1. If the temperature of saturated air at 20° C drops to 10° C abruptly, the relative humidity of the air will increase abruptly.
2. Rise in the relative humidity will lead to condensation or sublimation of water vapour in the air. This in turn, will lead to precipitation or snowfall.
In simple words: An abrupt temperature drop in saturated air will cause the air to become supersaturated, leading to immediate condensation or sublimation of water vapor, which can result in precipitation like rain or snow.

🎯 Exam Tip: This highlights the dew point concept; a temperature drop below the dew point causes excess moisture to condense, leading to precipitation.

Open-Ended Question:

Question a. Explain the effect of humidity on human life.

Answer:
1. High humidity increases the rate of sweating and respiration. This adversely affects the daily functioning.
2. Low humidity with pleasant atmosphere, have favourable effects on the daily routine.
3. High humidity leads to late drying up of clothes and early spoiling of food materials.
4. Low humidity leads to early drying up of clothes and late spoiling of food materials.
In simple words: Humidity significantly impacts human life by influencing comfort levels, health, food preservation, and the drying of clothes. High humidity often causes discomfort and faster food spoilage, while moderate humidity can be pleasant.

🎯 Exam Tip: When answering open-ended questions, provide a comprehensive view by discussing both positive (moderate) and negative (high/very low) impacts of humidity on various aspects of daily life.