Legacy IAS · NCERT Class 7 · Exploring Society: India and Beyond
Chapter 2
Understanding the Weather
India and the World: Land and the People · Comprehensive Study Notes + MCQ Practice
"A change in the weather is sufficient to create the world and oneself anew."
— Marcel Proust, French novelist
Content based on NCERT Class 7 — Exploring Society: India and Beyond, Part 1, Chapter 2 (Reprint 2026–27). All credit to NCERT. Compiled & formatted by Legacy IAS, Bengaluru for UPSC / State PCS preparation.
00
Quick Facts at a Glance
🌦️ Chapter 2 — Key Numbers & Facts
1875
Year India Meteorological Department (IMD) was established
5
Elements of weather: Temperature, Precipitation, Atmospheric Pressure, Wind, Humidity
6–18 km
Height of troposphere from ground
1013 mb
Normal atmospheric pressure at sea coast (millibars)
<1000 mb
Pressure below which a 'depression' is indicated
650 mb
Atmospheric pressure at Khardung La, Ladakh (5600+ m)
4800 m
Altitude of AWS set up by NDMA at glacial lake, Sikkim (2023)
20–40%
Relative humidity in dry weather
60–80%
Relative humidity in humid weather
km/h
Unit of wind speed measured by anemometer
4
IMD colour-coded warning levels: Green, Yellow, Orange, Red
mm
Unit used to measure rainfall (rain gauge)
⚠️ UPSC / State PCS — Chapter Importance
This chapter is important for Environment, Geography, and Science & Technology sections of UPSC Prelims and State PCS. Frequently tested facts: IMD establishment year (1875), its motto from Manusmṛiti, the five weather elements and their instruments, the AWS in Sikkim, IMD colour-coded warning system, and atmospheric pressure values.
01
What is Weather? — Atmosphere & Troposphere
Weather is the state of the Earth's atmosphere at a particular time and place.
The atmosphere is the layer of gases that surrounds the Earth — in the case of our Earth, we call these gases 'air'.
Fig. 2.2 · Layers of Earth's atmosphere — Troposphere (closest to Earth), Tropopause, Stratosphere, and Ozone Layer. Almost all weather occurs in the Troposphere.
| Position | The layer closest to the surface of the Earth; where all land-based plants and animals (including humans) live and breathe |
| Weather Phenomena | Almost all weather phenomena take place in the troposphere |
| Height | Extends to a height of 6 to 18 kilometres from the ground |
| At Poles | Less thick at the poles — cold air contracts |
| At Tropics | Thicker in the tropical zone — warmer air expands |
| Above Troposphere | Tropopause (boundary) → Stratosphere (contains Ozone Layer) |
🔍 Let's Explore
What are some of the words in your local language that you use to describe the weather? Hot, cold, warm, chilly, crisp, pleasant, and so on, are commonly used terms in English.
02
Five Elements of Weather
| Temperature | How hot or cold the atmosphere is |
| Precipitation | Any form of water — such as rain, snow, sleet or hail — that falls from the sky |
| Atmospheric Pressure | The weight of the air above us, felt on the Earth's surface |
| Wind | The movement of air, including its speed and direction |
| Humidity | The amount of water vapour in the air |
🔖 Key Definitions from NCERT Margin
- Water vapour: Water in gaseous form (instead of liquid form)
- Sleet: Frozen or partly frozen rain
- Hail: Small, hard balls of ice that fall from the sky like rain
- Forecast: To predict or find out in advance (in our case, the weather)
💡 Think About It — Krishnan & Amir
Krishnan from Chennai tells Amir in Kashmir that it has become "chilly" in Chennai. But what is cold for Krishnan may be quite pleasant for Amir! This shows why we need standardised measurement — unless we measure temperature in commonly agreed units (°C or °F), communication about weather is subjective and unreliable.
📝 Before We Move On — Chapter Summary
- Temperature, humidity, precipitation, wind and atmospheric pressure together define the weather at a particular place.
- In different times or situations, one element is dominant — rainfall in July, temperature in May and December, atmospheric pressure when a cyclone is moving, and wind when a loo (strong, hot and dusty winds blowing in north India in summers) is blowing or forest fires are spreading.
- Weather is closely linked to climate (discussed in the next chapter).
03
Traditional Weather Forecasting — Nature's Clues
From early times, humans have closely observed Nature and learnt to read her signals to forecast the weather. This knowledge has been passed down from generation to generation.
Even today, in many parts of India, people use traditional ways to predict the weather, especially the arrival of the monsoon.
Fig. 2.3.1–2.3.3 · Nature's clues: Ants shifting eggs to higher ground (indicates heavy rain); Frog croaking in Western Ghats (expectation of rain); Pine cones — close in humid conditions to protect seeds, open in dry conditions to release seeds.
| Ants shifting eggs to higher ground | Indicates an expected change in weather, especially heavy rain |
| Frogs croaking loudly | In expectation of rain (especially in Western Ghats forests) |
| Pine cones | Open and close driven by environmental humidity. Close in humid conditions to protect seeds; open in dry conditions to release seeds, ensuring they spread in favourable weather |
| Birds flying low | Indicates an expected change in weather |
| Squirrels gathering nuts | Provides information about coming rain or storms |
🔍 Let's Explore
Talk to elders in your neighbourhood and ask them how they predict the weather. What signs do they observe? Document any sayings in your regional language that refer to weather prediction.
Meteorology is the systematic study of weather and its evolution — and is the basis for weather forecasting. In the last few centuries, scientists have worked out methods to measure and monitor the elements of weather with great precision. Based on those inputs, meteorologists try to predict how the weather will behave in a particular region after a few hours, a few days, or even a few weeks.
04
Weather Instruments — Temperature (Thermometer)
🔖 Let's Remember — Temperature Scales
- Two main temperature scales: Celsius (°C) and Fahrenheit (°F)
- Example: 15°C = 59°F
- Types of thermometers: Clinical thermometer, Laboratory thermometer, Digital thermometers (more precise; can record more data)
- Some thermometers use a coloured liquid that expands when temperature increases.
| Range of Temperature | Maximum temperature minus Minimum temperature during a particular period (usually 24 hours) |
| Mean Daily Temperature | Maximum temperature plus Minimum temperature of the day, divided by two |
| Ambient Temperature | Temperature of the immediate surroundings |
| Statistics | The technique of gathering and analysing information/data in order to detect patterns, understand events, or make predictions |
📌 Don't Miss Out — India Meteorological Department (IMD)
- The India Meteorological Department was set up in 1875.
- Its motto is ādityāt jāyate vriṣhti, meaning "From the sun arises rain."
- The phrase comes from the ancient text Manusmṛiti.
- The complete sentence reads: "From the sun arises rain, from rain comes food, and from food, living beings originate."
- The connection: Sun → Evaporation of water → Water vapour → Clouds → Rain. This is the water cycle.
⚠️ UPSC Alert — IMD Facts
IMD established in 1875. Motto from Manusmṛiti: "ādityāt jāyate vriṣhti" = "From the sun arises rain." These are frequently tested in UPSC Prelims and State PCS exams.
05
Weather Instruments — Precipitation (Rain Gauge)
Fig. 2.6 · Rain Gauge — consists of a collecting funnel, measuring tube, and measuring scale. Water collected is measured in millimetres (mm).
| Instrument | Rain Gauge — measures the amount of rainfall |
| Components | Collecting funnel → Measuring tube → Measuring scale |
| Working Principle | Rain falls into the funnel → collected in cylinder → scale measures the depth of water collected |
| Unit | Millimetres (mm) — e.g., if height of water collected is 5 mm, the area received 5 mm of rainfall |
| Placement | In an open area, away from obstructions; on a flat surface that will not tilt with wind |
06
Weather Instruments — Atmospheric Pressure (Barometer)
Fig. 2.7 · Atmospheric Pressure — Lower pressure and cooler air at higher altitude (hilltop); higher pressure and warmer air at lower altitude (ground level). Air moves from high to low pressure.
Fig. 2.8 · Khardung La Top, Ladakh — over 5600 metres (18,380 feet) above sea level; atmospheric pressure ≈ 650 millibars; army personnel serve here despite extremely low oxygen levels.
| Definition | The pressure exerted by the weight of the air above and around us |
| Instrument | Barometer |
| Unit | Millibar (mb) |
| Normal Pressure (Sea Coast) | Around 1013 mb |
| Depression | Pressure below 1000 mb — indicates a depression (low-pressure system), which can develop into a storm or cyclone |
| At Higher Altitude | Atmospheric pressure is lower — air gets thinner, less oxygen → breathlessness, dizziness, fatigue |
| Khardung La, Ladakh | Over 5600 metres above sea level; pressure ≈ 650 mb; army personnel serve here |
| Acclimatise | To adjust to a new climate or new condition; people at high altitude must acclimatise by pausing on the way up |
| Weather feels 'heavy' | This is related to atmospheric pressure — felt before a thunderstorm |
💡 Think About It
Why is measuring atmospheric pressure important? It helps: Meteorologists detect depressions and predict storms/cyclones; pilots and sailors plan flights and voyages; military personnel at high-altitude posts monitor conditions; mountain climbers plan safe ascents.
07
Weather Instruments — Wind (Wind Vane & Anemometer)
Fig. 2.9 · Wind-dispersed seeds — Cotton seeds, dandelion seeds, grass seeds, winged seeds. Wind plays a crucial role in seed dispersal; without wind, these seeds would not spread to new locations.
Fig. 2.10 · Left: Wind vane (wind sock) on the airport tarmac — helps pilots judge wind direction during take-off and landing. Right: Anemometer — 3-cup rotating instrument that measures wind speed in km/h.
| Definition | Wind is the movement of air from areas of high pressure to areas of low pressure |
| Two Key Factors | Speed and Direction |
| Wind Vane (Weather Vane) | Has a rotating arm with a pointer at one end and a tail at the other; wind pushes the tail, pointer turns in the direction of wind; responds to even light breeze |
| Wind Sock | Wind vane on the airport tarmac; helps pilots judge wind direction during take-off and landing; also used in industries releasing ash or gases |
| Anemometer | Has 3 or 4 metal cups on a vertical shaft; stronger wind = faster rotation; meter counts spins per unit time; calculates wind speed in km/h |
| Importance of Wind Data | Weather forecasting; air pilots; sailors; farmers (predict direction of rain); greater wind speed dries soil faster |
08
Weather Instruments — Humidity (Hygrometer)
| Definition | The amount of water vapour present in the air; also depends on temperature, wind, pressure, and location |
| Instrument | Hygrometer (several types based on different principles) |
| Measurement | Relative Humidity (expressed as percentage) |
| 0% Relative Humidity | Air with absolutely no water vapour (theoretical — impossible in natural conditions) |
| 100% Relative Humidity | Air fully saturated with water vapour |
| Dry Weather | Relative humidity between 20% and 40% |
| Humid Weather | Relative humidity between 60% and 80% |
| Industrial Importance | Critical in food processing; Museums monitor humidity to preserve exhibits in a dry environment |
🔖 Key Principles of Humidity
- When water evaporates, it causes a cooling effect.
- If humidity is already high, water evaporates slowly — that's why rainy days feel sticky.
- At 84% humidity (like Kochi), wet clothes dry slower than at 52% humidity (like Delhi).
- Higher humidity → more sweating (body's cooling mechanism); but sweat evaporates slowly → you feel hotter and stickier.
💡 Think About It
If humidity in Delhi is 52% and in Kochi it is 84%, wet clothes dry faster in Delhi (lower humidity = faster evaporation). You are likely to sweat more in Kochi (higher humidity = body sweats more to cool itself, but sweat evaporates slowly making you feel hotter).
09
Weather Stations & Automated Weather Station (AWS)
A weather station brings all weather-measuring instruments together, making it easy to measure and track the weather. Readings are taken at regular intervals, which helps in mapping and forecasting the weather.
Fig. 2.12 · Automated Weather Station (AWS) at a glacial lake of Sikkim — set up by NDMA in 2023 at altitude >4800 metres above sea level; provides early information about upcoming weather conditions.
| Full Form | Automated Weather Station |
| Nature | A self-operating system using various sensors to measure and record weather data without human intervention |
| Parameters Measured | Temperature, humidity, wind speed and direction, precipitation, and atmospheric pressure |
| Applications | Agriculture, aviation, navigation, environmental monitoring, and more |
| NDMA Sikkim AWS (2023) | In 2023, National Disaster Management Authority (NDMA) set up an AWS at a glacial lake of Sikkim at altitude of more than 4800 metres above sea level; provides early information about upcoming weather conditions |
⚠️ UPSC Alert — AWS at Sikkim Glacial Lake
In 2023, NDMA set up an AWS at a glacial lake of Sikkim at altitude >4800 m. This is significant for early warning systems for glacial lake outburst floods (GLOFs) — a major disaster risk in Himalayan states. Frequently tested in UPSC/State PCS context questions on disaster management.
10
Predicting the Weather — IMD & Warning System
Fig. 2.13 · India: Weather Warning Map issued by IMD on 19 May 2024. Colour coding: Green = No Warning; Yellow = Watch (Be Updated); Orange = Alert (Be Prepared); Red = Warning (Take Action). Icons show: Fog, Heavy/Very Heavy/Extremely Heavy Rain, Heavy Snow, Hailstorm, Dust Storm, Heat Wave, Cold Wave, Cold Day, Ground Frost, Strong Surface Winds, Thunder & Lightning, Hot and Humid.
| 🟢 Green | No Warning |
| 🟡 Yellow | Watch — Be Updated |
| 🟠 Orange | Alert — Be Prepared |
| 🔴 Red | Warning — Take Action |
| Fog | Reduced visibility conditions |
| Heavy Rain / Very Heavy Rain / Extremely Heavy Rain | Increasing levels of rainfall severity |
| Heavy Snow | Significant snowfall expected |
| Hailstorm | Ice balls falling from sky |
| Dust Storm | Strong winds carrying dust |
| Heat Wave | Extremely high temperatures |
| Cold Wave | Extremely low temperatures |
| Cold Day | Maximum temperature significantly below normal |
| Ground Frost | Frost forming on ground surface |
| Strong Surface Winds | High wind speeds at ground level |
| Thunder & Lightning | Electrical storm activity |
| Hot and Humid | High temperature combined with high humidity |
Accurate predictions help:
- Fishermen warned against venturing out when stormy weather is expected at sea.
- Coastal areas evacuated if a cyclone is expected.
- Local governments mobilise resources and prepare for disasters.
- Climate change makes extreme weather (droughts, floods, cyclones) more frequent — making weather prediction more important than ever.
11
Key Terms Glossary
Weather
State of the Earth's atmosphere at a particular time and place.
Atmosphere
The layer of gases surrounding the Earth; we call these gases 'air'.
Troposphere
Layer closest to Earth's surface (6–18 km); where all weather occurs and all life exists.
Meteorology
The systematic study of weather and its evolution; the basis for weather forecasting.
Precipitation
Any form of water (rain, snow, sleet, hail) that falls from the sky.
Sleet
Frozen or partly frozen rain.
Hail
Small, hard balls of ice that fall from the sky like rain.
Water Vapour
Water in gaseous form (instead of liquid form).
Thermometer
Instrument for measuring temperature (in °C or °F).
Rain Gauge
Instrument for measuring precipitation (rainfall in mm).
Barometer
Instrument for measuring atmospheric pressure (in millibars, mb).
Wind Vane
Instrument for measuring wind direction; pointer turns in direction of wind.
Anemometer
Instrument for measuring wind speed (in km/h); has 3 or 4 rotating cups.
Hygrometer
Instrument for measuring humidity (relative humidity in %).
Relative Humidity
Percentage of water vapour in the air: 0% = completely dry (theoretical); 100% = fully saturated.
Depression
A low-pressure system (below 1000 mb) that can develop into a storm or cyclone.
Acclimatise
To adjust to a new climate or new condition (e.g., adjusting to high altitude).
AWS
Automated Weather Station — self-operating system using sensors to record weather data without human intervention.
Loo
Strong, hot, and dusty winds that blow in north India in summers.
Ambient
Of the immediate surroundings (as in 'ambient temperature').
📝 Before We Move On — NCERT Chapter Summary
- Temperature, humidity, precipitation, wind and atmospheric pressure together define the weather at a particular place.
- The condition of these elements is measured using special instruments. Data collected from these help us to monitor and predict the weather.
- In different times or situations, one of the elements is dominant — rainfall in July; temperature in May and December; atmospheric pressure when a cyclone is moving; wind when a loo is blowing or forest fires are spreading.
- Weather is closely linked to climate — discussed in the next chapter.
MCQ Practice Bank — Chapter 2
Understanding the Weather · 20 UPSC-Standard Questions
How to attempt: Click any option (A / B / C / D) to submit your answer. Correct answers turn green ✓; wrong answers turn red ✗ (correct answer shown automatically). Explanation appears after each attempt. Your live score updates as you go. After all 20 questions, a final scorecard appears.
Q 1
Which of the following statements about the troposphere is/are correct?
1. The troposphere is the layer of Earth's atmosphere closest to the surface.
2. Almost all weather phenomena take place in the troposphere.
3. The troposphere is thicker at the poles and thinner in the tropical zone.
4. The troposphere extends to a height of 6 to 18 kilometres from the ground.
Select the correct answer:
1. The troposphere is the layer of Earth's atmosphere closest to the surface.
2. Almost all weather phenomena take place in the troposphere.
3. The troposphere is thicker at the poles and thinner in the tropical zone.
4. The troposphere extends to a height of 6 to 18 kilometres from the ground.
Select the correct answer:
Q 2
Consider the following pairs of weather elements and their correct definitions:
1. Temperature — How hot or cold the atmosphere is
2. Precipitation — The amount of water vapour present in the air
3. Atmospheric Pressure — The weight of the air above us, felt on the Earth's surface
4. Humidity — Any form of water (rain, snow, sleet, hail) that falls from the sky
Which of the pairs given above is/are correctly matched?
1. Temperature — How hot or cold the atmosphere is
2. Precipitation — The amount of water vapour present in the air
3. Atmospheric Pressure — The weight of the air above us, felt on the Earth's surface
4. Humidity — Any form of water (rain, snow, sleet, hail) that falls from the sky
Which of the pairs given above is/are correctly matched?
Q 3
With reference to the India Meteorological Department (IMD), consider the following statements:
1. The IMD was set up in 1875.
2. Its motto is 'ādityāt jāyate vriṣhti', meaning 'From the sun arises rain.'
3. This phrase is taken from the ancient text Arthashastra.
4. The complete sentence reads: 'From the sun arises rain, from rain comes food, and from food, living beings originate.'
Which of the statements given above is/are correct?
1. The IMD was set up in 1875.
2. Its motto is 'ādityāt jāyate vriṣhti', meaning 'From the sun arises rain.'
3. This phrase is taken from the ancient text Arthashastra.
4. The complete sentence reads: 'From the sun arises rain, from rain comes food, and from food, living beings originate.'
Which of the statements given above is/are correct?
Q 4
What is the correct formula for calculating 'Mean Daily Temperature' as used in meteorology?
Q 5
A rain gauge measures precipitation by:
1. Collecting rainwater in a funnel that directs it into a measuring cylinder
2. Using a scale attached to the cylinder to measure the depth of water collected
3. Expressing rainfall in millimetres — e.g., 5 mm means the height of water collected is 5 mm
4. Using electronic sensors to measure the electrical conductivity of rainwater
Which of the statements given above is/are correct?
1. Collecting rainwater in a funnel that directs it into a measuring cylinder
2. Using a scale attached to the cylinder to measure the depth of water collected
3. Expressing rainfall in millimetres — e.g., 5 mm means the height of water collected is 5 mm
4. Using electronic sensors to measure the electrical conductivity of rainwater
Which of the statements given above is/are correct?
Q 6
With reference to atmospheric pressure, consider the following statements:
1. Atmospheric pressure is higher near the sea coast and lower at higher altitudes.
2. Normal atmospheric pressure at the sea coast is around 1013 millibars.
3. A pressure below 1000 mb indicates a depression, which can develop into a cyclone.
4. At Khardung La in Ladakh (5600+ metres), the atmospheric pressure is generally about 650 millibars.
Which of the statements given above is/are correct?
1. Atmospheric pressure is higher near the sea coast and lower at higher altitudes.
2. Normal atmospheric pressure at the sea coast is around 1013 millibars.
3. A pressure below 1000 mb indicates a depression, which can develop into a cyclone.
4. At Khardung La in Ladakh (5600+ metres), the atmospheric pressure is generally about 650 millibars.
Which of the statements given above is/are correct?
Q 7
Assertion (A): People travelling to high-altitude places are advised to pause on the way to acclimatise.
Reason (R): At high altitudes, the air gets thinner, atmospheric pressure is lower, and there is less oxygen available — causing breathlessness, dizziness, or fatigue.
Select the correct answer:
Reason (R): At high altitudes, the air gets thinner, atmospheric pressure is lower, and there is less oxygen available — causing breathlessness, dizziness, or fatigue.
Select the correct answer:
Q 8
Wind is defined as the movement of air from areas of _____ pressure to areas of _____ pressure.
Q 9
Consider the following statements about wind-measuring instruments:
1. A wind vane (weather vane) indicates the direction from which the wind is blowing.
2. An anemometer measures wind speed; it has three or four metal cups on a vertical shaft.
3. A 'wind sock' is a type of wind vane used on airport tarmacs to help pilots during take-off and landing.
4. Anemometer measures wind speed in millibars per hour (mb/h).
Which of the statements given above is/are correct?
1. A wind vane (weather vane) indicates the direction from which the wind is blowing.
2. An anemometer measures wind speed; it has three or four metal cups on a vertical shaft.
3. A 'wind sock' is a type of wind vane used on airport tarmacs to help pilots during take-off and landing.
4. Anemometer measures wind speed in millibars per hour (mb/h).
Which of the statements given above is/are correct?
Q 10
Consider the following statements about humidity:
1. Humidity refers to the amount of water vapour present in the air.
2. Humidity is measured as 'relative humidity'; air saturated with water vapour has 100% relative humidity.
3. Dry weather typically has relative humidity between 20% and 40%.
4. The instrument used to measure humidity is called a barometer.
Which of the statements given above is/are correct?
1. Humidity refers to the amount of water vapour present in the air.
2. Humidity is measured as 'relative humidity'; air saturated with water vapour has 100% relative humidity.
3. Dry weather typically has relative humidity between 20% and 40%.
4. The instrument used to measure humidity is called a barometer.
Which of the statements given above is/are correct?
Q 11
Match the weather instruments with the elements they measure:
1. Thermometer — (a) Humidity
2. Rain gauge — (b) Wind direction and speed
3. Barometer — (c) Temperature
4. Hygrometer — (d) Precipitation
5. Anemometer — (e) Atmospheric pressure
Which of the following is the correct matching?
1. Thermometer — (a) Humidity
2. Rain gauge — (b) Wind direction and speed
3. Barometer — (c) Temperature
4. Hygrometer — (d) Precipitation
5. Anemometer — (e) Atmospheric pressure
Which of the following is the correct matching?
Q 12
Consider the following traditional natural observations used for weather forecasting in India:
1. Ants shifting their eggs to higher ground indicates expected heavy rain.
2. Frogs croaking loudly indicates dry weather conditions ahead.
3. Pine cones open in humid conditions to protect their seeds and close in dry conditions to release them.
4. Birds flying low indicates an expected change in weather.
Which of the statements given above is/are correct?
1. Ants shifting their eggs to higher ground indicates expected heavy rain.
2. Frogs croaking loudly indicates dry weather conditions ahead.
3. Pine cones open in humid conditions to protect their seeds and close in dry conditions to release them.
4. Birds flying low indicates an expected change in weather.
Which of the statements given above is/are correct?
Q 13
Consider the following statements about an Automated Weather Station (AWS):
1. An AWS is a self-operating system that measures and records weather data using sensors.
2. In 2023, NDMA set up an AWS at a glacial lake of Sikkim at over 4800 metres altitude.
3. AWS stations are used only in agriculture and aviation sectors.
4. An AWS can measure temperature, humidity, wind speed and direction, precipitation, and atmospheric pressure.
Which of the statements given above is/are correct?
1. An AWS is a self-operating system that measures and records weather data using sensors.
2. In 2023, NDMA set up an AWS at a glacial lake of Sikkim at over 4800 metres altitude.
3. AWS stations are used only in agriculture and aviation sectors.
4. An AWS can measure temperature, humidity, wind speed and direction, precipitation, and atmospheric pressure.
Which of the statements given above is/are correct?
Q 14
Which of the following correctly describes the India Meteorological Department's four-colour subdivision warning system?
Q 15
Assertion (A): The measurement of humidity is important not only in weather forecasting but also in industries like food processing and in museums.
Reason (R): High humidity can spoil food products and damage museum exhibits, which are best preserved in a dry environment.
Select the correct answer:
Reason (R): High humidity can spoil food products and damage museum exhibits, which are best preserved in a dry environment.
Select the correct answer:
Q 16
Consider the following statements about relative humidity:
1. Air that would contain absolutely no water vapour would have 0% relative humidity (theoretical).
2. Humid weather typically falls between 60% and 80% relative humidity.
3. If humidity in Delhi is 52% and in Kochi it is 84%, wet clothes will dry faster in Kochi.
4. When water evaporates, it causes a cooling effect; higher humidity means slower evaporation.
Which of the statements given above is/are correct?
1. Air that would contain absolutely no water vapour would have 0% relative humidity (theoretical).
2. Humid weather typically falls between 60% and 80% relative humidity.
3. If humidity in Delhi is 52% and in Kochi it is 84%, wet clothes will dry faster in Kochi.
4. When water evaporates, it causes a cooling effect; higher humidity means slower evaporation.
Which of the statements given above is/are correct?
Q 17
Which of the following statements about 'loo' is correct, as mentioned in NCERT Chapter 2?
Q 18
Consider the following statements about how weather predictions help society:
1. Fishermen are warned about venturing out in their boats when stormy weather is expected at sea.
2. Coastal areas can be evacuated if a cyclone is predicted to make landfall.
3. Weather predictions help local governments mobilise resources for disaster preparedness.
4. According to NCERT, weather predictions are less important today because climate change is well-understood.
Which of the statements given above is/are correct?
1. Fishermen are warned about venturing out in their boats when stormy weather is expected at sea.
2. Coastal areas can be evacuated if a cyclone is predicted to make landfall.
3. Weather predictions help local governments mobilise resources for disaster preparedness.
4. According to NCERT, weather predictions are less important today because climate change is well-understood.
Which of the statements given above is/are correct?
Q 19
Consider the following statements about the elements of weather and their relationship:
1. Temperature, humidity, precipitation, wind, and atmospheric pressure together define the weather at a particular place.
2. In July, rainfall is the dominant weather element in India.
3. During a cyclone, atmospheric pressure is the most critical element being monitored.
4. When a loo blows in north India, wind is the dominant element affecting daily life.
Which of the statements given above is/are correct?
1. Temperature, humidity, precipitation, wind, and atmospheric pressure together define the weather at a particular place.
2. In July, rainfall is the dominant weather element in India.
3. During a cyclone, atmospheric pressure is the most critical element being monitored.
4. When a loo blows in north India, wind is the dominant element affecting daily life.
Which of the statements given above is/are correct?
Q 20
Consider the following statements about 'sleet' and 'hail':
1. Sleet is frozen or partly frozen rain.
2. Hail refers to small, hard balls of ice that fall from the sky like rain.
3. Both sleet and hail are forms of precipitation.
4. Sleet is more common in tropical regions, while hail is more common in polar regions.
Which of the statements given above is/are correct?
1. Sleet is frozen or partly frozen rain.
2. Hail refers to small, hard balls of ice that fall from the sky like rain.
3. Both sleet and hail are forms of precipitation.
4. Sleet is more common in tropical regions, while hail is more common in polar regions.
Which of the statements given above is/are correct?
