Class 11 Geography Chapter 10 NCERT Solutions 2026-27

Quick reading. Each option matches one textbook definition from the chapter.

1. For human beings, the key life-supporting gas is oxygen. Water vapour and dust matter for weather, but they do not replace oxygen.
2. Liquid water becomes vapour when heat changes its state. NCERT names this change evaporation.
3. Transpiration also adds moisture, but it is water loss from plants. It is not the general liquid-to-vapour change asked here.
4. Saturated air means the air has reached its full water-vapour holding capacity at that temperature.
5. Relative humidity compares present moisture with capacity. Absolute humidity gives actual weight of water vapour per unit volume.
6. Cirrus clouds are thin, detached and feathery clouds found at the highest level in this list.

Why this matters. The MCQ block is vocabulary based. Do not guess from common weather words. Match each option with the NCERT definition.

Choose oxygen, evaporation, saturated air and cirrus: (d), (c), (d) and (a).

List method. The safest answer names the form first and then states how it reaches the surface.

1. Precipitation starts after continuous condensation in free air.
2. When the air cannot support the condensed particles, gravity pulls them down.
3. If the falling moisture remains liquid, it is rainfall.
4. If the temperature is below freezing point, the moisture forms fine snow flakes and falls as snowfall.
5. If raindrops freeze into small rounded ice pieces before reaching the ground, they become hailstones.
6. If raindrops or melted snow refreeze near the ground, the form is called sleet.

Why this matters. NCERT uses precipitation as the wider term. Rain, snow, hail and sleet are the forms, not separate weather systems.

Rainfall, snowfall and hailstones are three types; sleet is also a form of precipitation.

Comparison view. Do not define it as just the amount of water vapour.

1. First note the actual water vapour present in a parcel of air.
2. Then note the maximum water vapour that the same parcel can hold at its present temperature.
3. Relative humidity is the ratio between these two quantities, written as a percentage.
4. If the air is close to its full capacity, relative humidity is high.
5. If the air is far below its full capacity, relative humidity is low.
6. Warm air can hold more water vapour than cold air, so a temperature change can alter the percentage even when moisture amount stays similar.

Why this matters. This answer tests the difference between actual amount and comparison with capacity. That comparison is the scoring phrase.

Relative humidity means actual moisture divided by full capacity at that temperature, expressed as a percentage.

Vertical-distribution angle. The lower atmosphere is both warmer and closer to moisture sources.

1. Evaporation from water bodies and transpiration from plants add most water vapour near the ground.
2. Air close to the surface is usually warmer, so it can retain more moisture.
3. When air rises, pressure decreases and the air expands.
4. Expansion cools the air, and the cooling lowers its moisture-holding capacity.
5. Once the air reaches dew point, extra water vapour condenses.
6. Condensation removes vapour from the air by forming droplets, clouds or ice crystals.
7. So the amount of vapour drops quickly with altitude instead of staying evenly mixed like nitrogen or oxygen.

Why this matters. The answer needs both supply and capacity. Source alone is incomplete, and temperature alone misses why lower air is wetter.

It falls with height because the vapour source is near the surface and colder upper air can hold much less moisture.

Process-first answer. Cloud names make sense only after the condensation step is clear.

1. Start with moist air, which contains water vapour.
2. When this air cools enough, it reaches dew point and cannot hold all the vapour.
3. The extra vapour changes into tiny droplets or ice crystals.
4. These particles need surfaces to form on, so dust, smoke and salt act as condensation nuclei.
5. When many such droplets or crystals gather in free air, a cloud is formed.
6. Cirrus clouds are high, thin and feathery.
7. Cumulus clouds look like cotton wool and have a flat base.
8. Stratus clouds form layers that cover large parts of the sky.
9. Nimbus clouds are dark, dense and linked with rain.
10. So the answer should include both the formation process and the classification list, because NCERT asks for both parts in the same question.

Why this matters. The classification is not random. It is based on form, height, density and transparency, so add one feature for each type.

Clouds are condensed droplets or ice crystals in free air, grouped into cirrus, cumulus, stratus and nimbus.

Distribution angle. Treat the answer like a map, moving from global belts to local controls.

1. The equatorial belt receives heavy rainfall because warm air rises and moisture supply is high.
2. Moving poleward, average rainfall generally decreases because air is colder and holds less moisture.
3. Sea-facing areas get more rain than interiors because moist air reaches them first.
4. Interiors lose rainfall because air masses drop moisture before moving far inland.
5. The eastern coasts near 35^∘ to 40^∘ north and south receive heavier rainfall because of warm currents and onshore winds in many regions.
6. The western margins between 45^∘ and 65^∘ north and south receive rainfall from the westerlies.
7. Mountains add a strong local control. Windward slopes force air upward, causing cooling and rain.
8. Leeward slopes receive dry descending air, so they get less rainfall.
9. The annual regimes can be grouped as heavy, moderate and low rainfall belts.
10. Seasonal distribution also matters because rainfall spread through the year is more useful than the same total falling in a short burst.
11. In a map-based answer, mention that heavy rainfall belts are not just equatorial; monsoon coasts and windward western coasts can also cross the 200 cm mark.
12. End with low rainfall areas such as high latitudes, rain-shadow zones and continental interiors, because these complete the contrast asked by distribution.

Why this matters. A strong long answer gives both the broad pattern and the reasons. Only listing regions makes the answer thin.

The world pattern depends on latitude, moisture source, prevailing winds, coasts, mountains and rain-shadow effects.

Dew-point method. The same cooling process creates different forms depending on temperature and location.

1. Condensation begins when moist air loses heat.
2. As cooling continues, the air reaches dew point and cannot hold all its water vapour.
3. If the cooled surface is above freezing point, water vapour changes into liquid droplets.
4. Those droplets collect on surfaces such as grass, leaves and stones, so the form is dew.
5. Clear sky helps the ground lose heat at night, while calm air lets the cooled layer stay near the surface.
6. High relative humidity supplies enough moisture for droplets to form.
7. If the surface and air near it are at or below freezing point, vapour deposits as ice crystals.
8. This solid form is frost. It is not frozen dew in the strict sense; it forms directly as ice crystals under freezing conditions.
9. Fog and clouds form when condensation takes place around nuclei in air, not on solid surfaces.
10. Mist is also a near-surface form, but it has lower density than fog and allows better visibility.
11. Thus the forms differ mainly by location of condensation, temperature of the surface or air and the size or density of suspended droplets.

Why this matters. The difference between dew and frost is the freezing-point line. Write that line clearly and the answer becomes exact.

Dew forms as liquid droplets when dew point is above freezing point; frost forms as ice crystals when it is at or below freezing point.

Project method. The task checks observation, classification and pattern reading, not memorised definitions.

1. Start the project file with the title Extreme Rainfall Reports from June to December.
2. Create a table with columns for serial number, newspaper date, place, state, rainfall amount, rainfall cause, impact and source.
3. Use June to September mainly for monsoon rainfall reports, but keep checking October to December for post-monsoon and cyclonic rain.
4. For mountain states, look for orographic rain, cloudburst and landslide reports.
5. For coastal states, look for depression, cyclone and very heavy rain reports.
6. For large cities, note urban waterlogging and drainage problems after heavy rainfall.
7. After filling the table, group the reports by region: mountains, coasts, plains and cities.
8. Then group them by month to see whether reports peak during monsoon months or during cyclonic months.
9. Finish with a short paragraph connecting the reports with Chapter 10 ideas such as precipitation, orographic rain, cyclonic rain and rainfall distribution.

Why this matters. This project becomes strong when it uses real dates and locations. The final pattern note shows that the student understood the geography behind the news.

Submit a dated rainfall-news table and a short analysis of region, month, cause and impact.