NDA General Studies · Geography · 55 questions · 2017 to 2026

NDA Atmosphere and climate previous year questions with solutions

Atmosphere and climate is the largest physical-geography topic in the General Ability Test, and the one UPSC has leaned on hardest since 2024. The old one-line recall of a wind or a layer has given way to statement sets lifted from the NCERT and Strahler. Every question UPSC has set on it since 2017, solved. Grouped by the method each needs, newest first; open a question for its answer and worked solution.

31.1 Composition and structure of the atmosphere (10)31.2 Insolation, heating of the atmosphere and temperature (4)31.3 Atmospheric pressure, the Coriolis force and winds (15)31.4 Humidity, condensation, clouds and precipitation (10)31.5 Air masses, fronts, cyclones and anticyclones (11)31.6 World climates and climatic hazards (5)

31.1 Composition and structure of the atmosphere

1. NDA 2026 (II)
Consider the following statements regarding the structure of the atmosphere:
I. The average height of the troposphere is higher nearer the poles than at the equator.
II. The mesosphere contains the ozone layer.
III. Radio waves transmitted from the Earth are reflected to the Earth by the ionosphere.
IV. In the mesosphere, temperature decreases with an increase in altitude.
Which of the statements given above are correct?
Answer and solution

Answer: (c) III and IV only

Method. structure of the atmosphere (NCERT)

I is false: the troposphere is highest at the Equator (about 18 km) and lowest near the poles (about 8 km). II is false: the ozone layer is in the stratosphere. III is true: the ionosphere reflects radio waves back to Earth. IV is true: temperature falls with height in the mesosphere (down to about -90 C at the mesopause). So III and IV only.

2. NDA 2026 (I)
Consider the following pairs:
Layers of Atmosphere — Characteristics
I. Troposphere — Absorbs ultraviolet radiation
II. Stratosphere — Changes in weather and climate
III. Mesosphere — Reflects radio waves back to the Earth
How many of the pairs given above are correctly matched?
Answer and solution

Answer: (a) None

Method. layers of the atmosphere (NCERT)

I is wrong: ultraviolet radiation is absorbed by the ozone in the stratosphere. II is wrong: weather and climate changes occur in the troposphere. III is wrong: radio waves are reflected by the ionosphere (NCERT places it above the mesopause, from about 80 to 400 km). No pair is correct, so (a) None.

3. NDA 2025 (II)
Consider the following statements with reference to structure of the Earth’s atmosphere:
1. Thickness of the troposphere is greatest at the equator
2. The air temperature of the tropopause is highest above the poles
3. The temperature in troposphere decreases at the rate of 1°F for every 165 m of height
Which of the statements given above is/⁠are correct?
Answer and solution

Answer: (b) 1 and 2 only

Method. structure of the atmosphere (NCERT)

Statement 1 is true: the troposphere is about 18 km thick at the Equator and about 8 km at the poles. Statement 2 is true: the tropopause is coldest over the Equator (about -80 C) and warmer over the poles (about -45 C). Statement 3 is false: the lapse rate is 1 C(not 1 F) per 165 m; 1 F per 165 m would be about 3.4 C per km. So 1 and 2 only.

4. NDA 2024 (I)
Which of the following statements regarding ‘aurora’ is/⁠are correct?
1. The solar wind upon reaching the Earth’s atmosphere is directed towards two magnetic poles and a colourful display of lights is seen in the night sky.
2. The particles interact with the different gases of the atmosphere and each gas glows with a particular colour.
3. In April 2023, aurora was captured in the night sky in India by the Indian Astronomical Observatory at Hanle, Ladakh.
Select the answer using the code given below:
Answer and solution

Answer: (d) 1, 2 and 3

Method. aurora

Statement 1 is true: charged particles of the solar wind are channelled by the magnetic field to the polar regions and produce the display. Statement 2 is true: particles collide with atmospheric gases and each gas glows in its own colour (oxygen green and red, nitrogen blue and purple). Statement 3 is true: in April 2023 aurora (a red arc) was recorded by the Indian Astronomical Observatory at Hanle, Ladakh. All three are correct.

5. NDA 2023 (II)
In which one of the following layers of the atmosphere all weather phenomenon occur?
Answer and solution

Answer: (b) Troposphere

Method. layer of weather

The troposphere holds almost all the water vapour, dust and clouds, so all weather phenomena occur in it (NCERT Class 11 FPG, Ch. 8).

6. NDA 2021 (II)
Which one of the following is the correct sequence of layers as we move from the Earth’s surface upwards?
Answer and solution

Answer: (b) Troposphere, Stratosphere, Mesosphere, Thermosphere

Method. layers of the atmosphere

From the surface upwards: troposphere, stratosphere, mesosphere, thermosphere (with the exosphere above) (NCERT Class 11 FPG, Ch. 8).

7. NDA 2021 (I)
The composition of gases in exosphere is
Answer and solution

Answer: (a) Helium and Hydrogen.

Method. exosphere

The exosphere is the uppermost layer, where the air is extremely thin and the light gases helium and hydrogen drift off into space (NCERT Class 11 FPG, Ch. 8).

8. NDA 2019 (II)
The normal lapse rate of temperature of Earth’s atmosphere drops to 0°C at the
Answer and solution

Answer: (b) upper boundary of the tropopause.

Method. lapse rate at the tropopause

The question means that the lapse rate (the rate of fall of temperature with height) becomes zero, not that the temperature reaches 0 C. The lapse rate of about 6.5 C per km in the troposphere falls to zero at the tropopause, where temperature stops falling and stays nearly constant (isothermal) before rising in the stratosphere. This is the base of the stratosphere, so (b). The stratopause (d) is the distractor: there temperature, having risen through the stratosphere, peaks near 0 C, but nothing 'drops' to it. Ionosphere and mesosphere are layers where temperature rises or falls strongly with height.

9. NDA 2018 (II)
Which one of the following statements about temperature is correct?
Answer and solution

Answer: (d) Temperature decreases with height in the troposphere at an average rate of 6.4 °C per kilometre.

Method. normal lapse rate of the troposphere

Temperature falls with height in the troposphere at the normal lapse rate, about 6.5 C per km (NCERT Class 11 FPG: 1 C per 165 m); Strahler rounds the same value (3.5 F per 1000 ft) to 6.4 C per km. (a) is false: in the stratosphere temperature rises with height because of ozone absorption. (b) is false for the same reason. (c) is false: it says temperature increases in the troposphere. (d) alone has the right direction and the right size to within rounding, so it is the intended answer; teach the NCERT figure of 6.5 C per km.

10. NDA 2017 (II)
Which one of the following gases is placed second in respect of abundance in the Earth's atmosphere?
Answer and solution

Answer: (a) Oxygen

Method. composition of dry air by volume

By volume dry air is about 78% nitrogen, 21% oxygen, 0.93% argon, 0.04% carbon dioxide (NCERT Class 11 FPG, Ch. 8, table of atmospheric gases). Nitrogen is first, so oxygen is second. Hydrogen is only a trace gas and carbon dioxide is fourth.

31.2 Insolation, heating of the atmosphere and temperature

11. NDA 2026 (I)
Consider the following statements about temperature inversion:
I. This happens when normal lapse rate gets inverted.
II. Winter nights with cloudy skies are conducive for temperature inversion.
III. Polar areas experience inversion throughout the year.
Which of the statements given above are correct?
Answer and solution

Answer: (c) I and III only

Method. temperature inversion (NCERT)

I is true: inversion is the reversal of the normal fall of temperature with height. II is false: the best conditions are long winter nights with clear skies, calm air and dry air, so that the ground radiates its heat freely. Cloud would trap the heat. III is true: the polar areas, with a permanent cold surface, have surface inversion all year. So I and III only.

12. NDA 2025 (II)
Which of the following are the factors that cause variation in the amount of insolation on the Earth?
1. Rotation of the earth on its axis
2. Length of the day
3. Distribution of land and water on the earth
Select the answer using the code given below:
Answer and solution

Answer: (b) 1 and 2 only

Method. factors of insolation (NCERT)

NCERT Class 11 FPG, Ch. 8, lists the factors that vary the amount of insolation: rotation of the Earth on its axis, angle of inclination of the sun's rays, length of the day, transparency of the atmosphere, and the land aspect. So statements 1 and 2 are in the list. Distribution of land and water affects how temperature differs from place to place (a factor controlling temperature, not insolation received), so 3 is out.

13. NDA 2024 (I)
Which of the following statements regarding air temperature is/⁠are correct?
1. Air temperature is measured at a standard height of 1.2 m (4.0 feet) above the ground surface.
2. The average rate of temperature decrease with height is termed as the environmental temperature lapse rate.
Select the answer using the code given below:
Answer and solution

Answer: (c) Both 1 and 2

Method. air temperature measurement and lapse rate

Statement 1 follows Strahler: air temperature is measured in a shelter at a standard height of about 1.2 m (4 ft) above the ground. Statement 2: the fall of temperature with height in the troposphere is the environmental temperature lapse rate (its average is the normal lapse rate). Both are accepted as correct.

14. NDA 2021 (II)
The Earth’s atmosphere is mainly heated by which one of the following?
Answer and solution

Answer: (c) Long wave terrestrial radiation

Method. heating of the atmosphere

Short-wave solar radiation passes mostly through the air and heats the Earth's surface; the surface then re-radiates long-wave (terrestrial) radiation, which the air absorbs. The atmosphere is therefore heated mainly from below by long-wave terrestrial radiation (NCERT Class 11 FPG, Ch. 8, heat budget).

31.3 Atmospheric pressure, the Coriolis force and winds

15. NDA 2026 (II)
Consider the following statements:
I. At the equator, the Coriolis force is zero and here the winds blow perpendicular to the isobars.
II. The Coriolis force is directly proportional to the angle of latitude.
III. The Coriolis force and the resultant wind do not blow parallel to the isobars at higher latitudes.
Which of the statements given above are correct?
Answer and solution

Answer: (d) I and II only

Method. Coriolis force (NCERT)

Statement I is true: the Coriolis force is zero at the Equator and the wind crosses the isobars there. Statement II repeats the NCERT Class 11 FPG, Ch. 9 wording that the force is directly proportional to latitude, maximum at the poles and absent at the Equator (strictly it goes as the sine of the latitude). Statement III is false: at higher latitudes the Coriolis force balances the pressure gradient force and the wind blows parallel to the isobars (geostrophic wind). So I and II.

16. NDA 2026 (II)
In the southern hemisphere, trade winds blow from:
Answer and solution

Answer: (b) South-East to North-West

Method. trade winds

Trade winds blow from the subtropical highs to the equatorial low. In the Southern Hemisphere they are deflected to the left and are the south-east trades, blowing from the south-east towards the north-west. (b).

17. NDA 2026 (I)
Which one of the following winds is responsible for wildfires in Southern California?
Answer and solution

Answer: (c) Santa Ana wind

Method. local winds and fires

The Santa Ana is the hot, dry offshore wind of Southern California, which fanned the Los Angeles fires of January 2025. The Diablo wind is the similar wind of the San Francisco Bay Area (northern California), the Jarbo Gap wind is a northern-California wind (Butte County), and the Chinook belongs to the Rockies.

18. NDA 2025 (I)
Which of the following statements with reference to Coriolis force is/⁠are correct?
1. Coriolis force acts perpendicular to the pressure gradient force
2. At the equator, the Coriolis force is zero and the wind blows perpendicular to the isobars
Select the answer using the code given below:
Answer and solution

Answer: (c) Both 1 and 2

Method. Coriolis force (NCERT)

NCERT Class 11 FPG, Ch. 9: the Coriolis force acts perpendicular to the pressure gradient force, so statement 1 is true. At the Equator the Coriolis force is zero and the wind blows perpendicular to the isobars (low pressure gets filled instead of intensifying), so statement 2 is true. Both are correct.

19. NDA 2024 (II)
Which one among the following local winds is NOT related to Mediterranean Sea?
Answer and solution

Answer: (a) Harmattan

Method. local winds of the Mediterranean

Khamsin (Egypt), Sirocco (Sahara to Italy and Sicily) and Mistral (southern France) all affect the Mediterranean. The Harmattan is the dry north-easterly of West Africa blowing from the Sahara to the Atlantic coast (Gulf of Guinea), not to the Mediterranean.

20. NDA 2024 (II)
Where is the Coriolis Effect the largest?
Answer and solution

Answer: (c) At the North Pole

Method. variation of the Coriolis effect

The Coriolis force varies as the sine of the latitude: zero at the Equator, increasing with latitude, maximum at the poles (NCERT Class 11 FPG, Ch. 9). Of the options only the North Pole is at maximum.

21. NDA 2023 (II)
Which one of the following is the usual unit of measurement for Air Pressure used in India?
Answer and solution

Answer: (b) Millibar

Method. unit of air pressure

Air pressure is measured in millibars (1 mb = 1 hPa); the standard sea-level value is 1013.25 mb. Centimetre is length, milligram mass and millilitre volume. The IMD now reports in hPa, the same numerical value.

22. NDA 2020 (I)
Which one of the following is a cold local wind?
Answer and solution

Answer: (c) Mistral

Method. hot versus cold local winds

The Mistral is the cold, dry wind blowing down the Rhone valley to the Mediterranean coast of France. The Santa Ana (southern California), Chinook (Rockies) and Loo (north India and Pakistan plains) are warm or hot dry winds.

23. NDA 2019 (I)
“Shamal” warm and dry wind is a “Local” wind found in
Answer and solution

Answer: (d) Mesopotamia

Method. local winds and their regions

The Shamal is a hot, dry north-westerly wind of Mesopotamia (Iraq) and the Persian Gulf. The Sahara's hot winds are the Sirocco, Simoom, Khamsin, and the West African one is the Harmattan.

24. NDA 2018 (II)
Statement I:
Geostrophic wind blows above a height of 600 metres, parallel to the isobars.
Statement II:
Geostrophic wind is the horizontal wind velocity, in which the Coriolis force balances the horizontal pressure force.
Answer and solution

Answer: (a) Both the statements are individually true and Statement II is the correct explanation of Statement I

Method. geostrophic wind

Statement II is the definition: the geostrophic wind is the horizontal wind in which the Coriolis force balances the pressure-gradient force. Because the two forces balance, the wind flows parallel to the isobars. Friction is negligible above the friction layer (about 600 m in Singh's account), so Statement I is true, and II explains why it blows parallel to the isobars. (a).

25. NDA 2018 (II)
Match List-I with List-II and select the correct answer using the code given below the Lists:
List-I (Local Wind)
A. Yamo
B. Black Roller
C. Bise
D. Haboob
List-II (Place)
1. Sudan
2. France
3. Japan
4. North America
Code:
A B C D
Answer and solution

Answer: (c) 3 4 2 1

Method. matching local winds to regions

Haboob is the dust-storm wind of Sudan (D-1). Bise is the cold dry wind of France and Switzerland (C-2). Black Roller is the dust storm of the North American Great Plains (B-4). The remaining pair is Yamo-Japan (A-3). The code A-3, B-4, C-2, D-1 is option (c). The three certain pairs alone (B-4, C-2, D-1) already single out (c).

Shortcut. Haboob = Sudan (D-1) and Bise = France (C-2) fix option (c) at once.

26. NDA 2018 (I)
Consider the following statements about Roaring Forties:
1. They are strong Westerly winds found in the oceans of Southern Hemisphere.
2. The strong east to west air currents are caused by the combination of air being displaced from the Equator towards the South Pole and the earth’s rotation and abundance of landmasses to serve as wind breaks.
Which of the statements given above is/⁠are correct?
Answer and solution

Answer: (a) 1 only

Method. Roaring Forties

Statement 1 is true: the Roaring Forties are strong westerlies of the Southern Hemisphere oceans, about 40-50 deg S. Statement 2 is false: westerlies blow from west to east, not east to west. The sparse land in those latitudes means few wind breaks, which is the cause of their strength. Only statement 1 is correct.

27. NDA 2018 (I)
Consider the following statements:
1. The doldrums is a low pressure area around Equator where the prevailing winds are calm.
2. Chinook is a hot and dry wind that blows in winter and therefore raises the temperature in a short time.
Which of the statements given above is/⁠are correct?
Answer and solution

Answer: (c) Both 1 and 2

Method. doldrums and Chinook

Statement 1: the doldrums are the equatorial low-pressure belt of calm, light and variable winds, so it is true. Statement 2: the Chinook is a warm, dry foehn wind on the eastern slopes of the Rockies; it blows mainly in winter and early spring and raises temperatures sharply within hours (the 'snow eater'), so it is true. Both are correct.

28. NDA 2018 (I)
Which one of the following is a local wind that blows out from Siberia?
Answer and solution

Answer: (b) Purga

Method. local winds of cold regions

The Purga is the violent cold wind and snowstorm of the Siberian tundra (Russia). Bora is the cold wind of the Adriatic, Mistral the cold wind of southern France, and 'blizzard' is a general term for a snowstorm, not a named local wind of Siberia.

29. NDA 2017 (II)
The Coriolis effect is the result of
Answer and solution

Answer: (c) Earth's rotation

Method. cause of the Coriolis effect

The Coriolis effect is the apparent deflection of moving air (or water) caused by the Earth's rotation: to the right in the Northern Hemisphere, to the left in the Southern (NCERT Class 11 FPG, Ch. 9). The pressure gradient is a separate force; axial tilt causes the seasons and revolution the year, not deflection.

31.4 Humidity, condensation, clouds and precipitation

30. NDA 2025 (I)
Which of the following statements with reference to Sleet is/⁠are correct?
1. Sleet is frozen raindrops and refrozen melted snow-water
2. It occurs when a layer of air with the temperature below freezing point overlies a warm layer near the ground surface
Select the answer using the code given below:
Answer and solution

Answer: (a) 1 only

Method. sleet (NCERT)

NCERT Class 11 FPG, Ch. 8: sleet is frozen raindrops and refrozen melted snow-water, so statement 1 is true. It forms when a layer of air above freezing overlies a sub-freezing layer near the ground: raindrops falling into the cold layer freeze into ice pellets. Statement 2 has the layers the wrong way round, so it is false. 1 only.

31. NDA 2025 (I)
Condensation of water vapour into water is influenced by which of the following factor/⁠factors?
1. Volume of air
2. Humidity
3. Temperature
Select the answer using the code given below:
Answer and solution

Answer: (d) 1, 2 and 3

Method. factors of condensation (NCERT)

NCERT Class 11 FPG, Ch. 8: condensation is influenced by the volume of air, temperature, pressure and humidity. Volume of air, humidity and temperature are all in this list, so 1, 2 and 3 are all correct.

32. NDA 2024 (I)
Which of the following statements regarding clouds is/⁠are correct?
1. Clouds are classified on the basis of altitude and their form.
2. According to altitude they are classified as High, Middle and Low clouds.
3. Stratus, Nimbostratus and Stratocumulus are high clouds.
Select the answer using the code given below:
Answer and solution

Answer: (b) 1 and 2 only

Method. classification of clouds

Statement 1 is true: clouds are classified by form and altitude (Strahler). Statement 2 is true: high, middle and low. Statement 3 is false: stratus, nimbostratus and stratocumulus are low clouds. So 1 and 2 only.

33. NDA 2024 (I)
Which of the following statements regarding humidity is/⁠are correct?
1. It is a ratio between the actual amount of water vapour present in the atmosphere and the maximum amount it can hold at a given temperature.
2. When the relative humidity is high, more water evaporates from the skin.
3. Higher the air temperature lower the relative humidity of the air.
Select the answer using the code given below:
Answer and solution

Answer: (c) 1 and 3 only

Method. humidity

Statement 1 is the definition of relative humidity, so it is true. Statement 2 is false: when relative humidity is high the air is nearly saturated and less water evaporates from the skin (hence the sticky feeling). Statement 3 is true: warmer air can hold more vapour, so for the same water-vapour content, relative humidity falls as temperature rises. So 1 and 3.

34. NDA 2022 (I)
According to the Indian Meteorological Department, which of the following is/⁠are the feature/⁠features of cloudburst?
1. Heavy precipitation in short period of time in a limited geographical area
2. It occurs generally during monsoon period and triggers flash flood and landslides
Select the correct answer using the code given below.
Answer and solution

Answer: (c) Both 1 and 2

Method. cloudburst (IMD)

IMD describes a cloudburst as a sudden, very heavy fall of rain (about 100 mm per hour or more) over a small area, roughly 20-30 sq km. Statement 1 is true. Statement 2 is also true: cloudbursts occur mostly in the monsoon, in hilly terrain, and trigger flash floods and landslides. Both are correct.

35. NDA 2022 (I)
Snow, sleet and hail are the forms of
Answer and solution

Answer: (a) precipitation

Method. forms of precipitation

Precipitation is water falling to the earth as rain, snow, sleet or hail (NCERT Class 11 FPG, Ch. 8). Condensation, transpiration and evaporation are not forms in which water reaches the ground.

36. NDA 2021 (I)
Which one of the following is not a form of condensation?
Answer and solution

Answer: (d) Sleet

Method. forms of condensation

Dew, fog and frost are products of condensation (NCERT Class 11 FPG, Ch. 8: forms of condensation are dew, frost, fog, mist and clouds). Sleet is a form of precipitation (frozen raindrops or refrozen melted snow).

37. NDA 2021 (I)
Which one of the following clouds is a rain-bearing cloud?
Answer and solution

Answer: (c) Nimbus cloud

Method. rain-bearing clouds

'Nimbus' means rain-bearing (nimbostratus and cumulonimbus). Cumulus is a fair-weather cloud, stratus gives at most drizzle, and cirrus is a high ice-crystal cloud that gives no rain.

38. NDA 2019 (I)
“Inversion of Rainfall” is associated with
Answer and solution

Answer: (a) Orographic rainfall

Method. inversion of rainfall

Inversion of rainfall is a feature of orographic rainfall on mountains: rainfall increases with height up to a zone of maximum precipitation (about 1000-1500 m in the Himalaya) and then decreases above it, because the air aloft has lost most of its moisture. (Leong / Singh, Climatology.)

39. NDA 2018 (II)
Which one of the following types of cloud is characterized by continuous precipitation?
Answer and solution

Answer: (c) Nimbostratus

Method. cloud type and precipitation

Nimbostratus is a thick, dark, low layer cloud that gives continuous rain or snow (Strahler / NCERT Class 11 FPG, Ch. 8 cloud types). Cumulonimbus gives showery, thundery rain, not continuous. Cumulus is a fair-weather cloud; cirrocumulus is a high cloud with no precipitation.

31.5 Air masses, fronts, cyclones and anticyclones

40. NDA 2026 (I)
Consider the following statements regarding extratropical cyclones:
I. They usually develop in the mid and high latitudes.
II. They affect a much larger area as compared to tropical cyclone.
III. They move from east to west.
Which of the statements given above are correct?
Answer and solution

Answer: (a) I and II only

Method. extratropical cyclones (NCERT)

I is true: they form in the middle and high latitudes, along the polar front. II is true: they cover a much larger area than the tropical cyclone. III is false: they move from west to east with the westerlies. So I and II only.

41. NDA 2025 (II)
Consider the following conditions favourable for the formation and intensification of Tropical Storms:
1. Presence of the Coriolis force
2. Upper divergence above the sea level system
3. High variations in the vertical wind speed
Which of the conditions given above is/⁠are correct?
Answer and solution

Answer: (c) 1 and 2

Method. conditions for tropical storms (NCERT)

NCERT Class 11 FPG, Ch. 9 lists the conditions: a large sea surface above 27 C; the presence of the Coriolis force; small variations in the vertical wind speed; a pre-existing weak low-pressure area; upper-level divergence above the sea-level system. So 1 and 2 are correct. 3 is wrong: variations in vertical wind speed must be small, since strong shear tears the storm apart.

42. NDA 2024 (II)
Match List I with List II and select the correct answer using the code given below the Lists:
List I (Tropical Cyclone)
A. Hurricanes
B. Willy Willy
C. Baguio
D. Typhoons
List II (Country)
1. China
2. Philippines
3. Australia
4. USA
Code:
A B C D
Answer and solution

Answer: (a) 4 3 2 1

Method. tropical cyclone names by region

Hurricanes are in the USA and Caribbean (A-4), Willy-Willy in Australia (B-3), Baguio in the Philippines (C-2), Typhoons in China and the western Pacific (D-1). Code 4 3 2 1 is option (a).

43. NDA 2024 (I)
Consider the following statements regarding ‘fronts’ :
1. The movement of a front causes a slow change in weather in the area over which it moves.
2. Cold fronts are associated with thunderstorms.
3. Warm front is the boundary between an advancing mass of warm air where it is overriding and rising above a mass of colder air.
Which of the statements given above is/⁠are correct?
Answer and solution

Answer: (c) 2 and 3 only

Method. fronts

Statement 1 is false: a moving front brings an abrupt (rapid), not slow, change in weather. Statement 2 is true: cold fronts push under warm air, causing sharp uplift, cumulonimbus and thunderstorms. Statement 3 is true: a warm front is the boundary where advancing warm air overrides a colder air mass. So 2 and 3 only.

44. NDA 2024 (I)
Which of the following statements regarding cyclones and anti-cyclones is/⁠are correct?
1. In the Northern Hemisphere, cyclones rotate counter clockwise and anticyclones rotate clockwise.
2. Cyclones are often associated with cloudy or rainy weather, whereas anticyclones are often associated with fair weather.
3. In the Southern Hemisphere, the cyclonic spiral will be clockwise because the Coriolis force acts to the left.
Select the answer using the code given below:
Answer and solution

Answer: (d) 1, 2 and 3

Method. cyclones and anticyclones

Statement 1 is true: in the Northern Hemisphere cyclones spin counter-clockwise and anticyclones clockwise. Statement 2 is true: cyclones bring cloud and rain, anticyclones fair weather. Statement 3 is true: in the Southern Hemisphere the Coriolis force deflects wind to the left, so the cyclonic spiral is clockwise. All three are correct.

45. NDA 2024 (I)
Which of the following statements regarding tropical cyclones is/⁠are correct?
1. These storms develop during the summer and autumn in every tropical ocean except the South Atlantic and eastern South Pacific Oceans.
2. Tropical cyclones that occur in the North Atlantic and eastern North Pacific Oceans are known as typhoons.
3. Tropical cyclones that occur in the Indian and South Pacific Oceans are called cyclones.
Select the answer using the code given below:
Answer and solution

Answer: (c) 1 and 3 only

Method. tropical cyclones (Strahler)

Statement 1 is true: they form in summer and autumn in every tropical ocean except the South Atlantic and the south-eastern Pacific. Statement 2 is false: in the North Atlantic and eastern North Pacific they are called hurricanes; typhoons are in the western North Pacific. Statement 3 is true: in the Indian Ocean and South Pacific they are called cyclones. So 1 and 3.

46. NDA 2022 (II)
Consider the following statements about anticyclones:
1. Anticyclones are high pressure systems.
2. Air in the centre of the system must be subsiding.
3. Anticyclones are characterized by converging winds.
How many of the above statements is/⁠are correct?
Answer and solution

Answer: (b) 2

Method. anticyclones

The question asks how many statements are correct. Statement 1 is true: an anticyclone is a high-pressure system. Statement 2 is true: air subsides in the centre and spreads out near the surface. Statement 3 is false: anticyclones have diverging, not converging, winds (clockwise in the Northern Hemisphere). Two are correct, so option (b) '2' (the count).

47. NDA 2022 (I)
Nisarga, Gati, Nivar, Tauktae and Yaas are names of
Answer and solution

Answer: (d) cyclones

Method. names of tropical cyclones

These are names given to tropical cyclones of the North Indian Ocean in 2020-21 from the WMO/⁠ESCAP list: Nisarga (June 2020), Gati (Nov 2020), Nivar (Nov 2020), Tauktae (May 2021) and Yaas (May 2021).

48. NDA 2019 (I)
Which one of the following is NOT true in reference to Air mass?
Answer and solution

Answer: (c) Air mass develops in a cyclonic condition

Method. air masses

An air mass is a large body of air with nearly uniform temperature and humidity. It forms over a source region (tropical or polar, on land or sea) where the air stays still for days under calm, high-pressure (anticyclonic) conditions, and it changes the weather of the regions it moves over. So (a), (b) and (d) are true. (c) is not true: a cyclonic condition, with converging and rising winds, does not allow the air to take on the properties of the surface.

49. NDA 2019 (I)
Which one of the following can be said to be essentially related to ‘Polar Front Theory’?
Answer and solution

Answer: (c) Temperate Cyclone

Method. Polar Front Theory

The Polar Front Theory of Bjerknes (1918) explains the origin and life cycle of the temperate (extratropical, mid-latitude) cyclone along the polar front, where cold polar easterlies meet warm subtropical westerlies. Tropical cyclones form without fronts.

50. NDA 2017 (II)
Consider the following characteristics of a tropical cyclone:
(1) A warm sea temperature of > 26° C
(2) High relative humidity of atmosphere at a height of > 700 m
(3) Atmospheric instability
The above mentioned characteristics are associated with which one of the following cycles of its development?
Answer and solution

Answer: (a) Formulation and initial stage

Method. conditions for the genesis of a tropical cyclone

The listed items are the favourable conditions for the birth of a tropical cyclone: sea-surface temperature above 26-27 C, high relative humidity in the lower-middle troposphere (the standard condition is stated at about 700 hPa) and atmospheric instability. They belong to the formation and initial-development stage (Savindra Singh, Climatology, life cycle of a tropical cyclone). Maturity, modification and decay are the later stages, when the storm moves over land or cool water and loses these supports.

31.6 World climates and climatic hazards

51. NDA 2026 (II)
A prolonged period of inadequate rainfall marked with mal-distribution of the same over time and space is known as:
Answer and solution

Answer: (d) Meteorological drought

Method. types of drought

Meteorological drought is the prolonged period of inadequate rainfall marked by mal-distribution over time and space (NCERT Class 11, India Physical Environment, Natural Hazards and Disasters; IMD). Agricultural drought concerns soil moisture and crop failure, and hydrological drought concerns low water in rivers, lakes and reservoirs.

52. NDA 2024 (I)
Which of the following statements regarding the World Climate Types and their relation with Inter Tropical Convergence Zone (ITCZ) is/⁠are correct?
1. Tropical Wet Climate is one of the world’s rainiest due to the dominance of the ITCZ over it.
2. Tropical Savanna Climate experiences a distinctive alternation of wet and dry seasons, caused chiefly by the seasonal shift in latitude of the subtropical highs and ITCZ.
3. The Tropical Monsoonal Climate experiences heavy rainfall as a consequence of the nearness of the ITCZ for much of the year.
Select the answer using the code given below:
Answer and solution

Answer: (b) 1 and 2 only

Method. climate types and the ITCZ

Statement 1 is true: the tropical wet climate lies under the ITCZ almost all year and is among the rainiest in the world. Statement 2 is true: the savanna climate has alternating wet and dry seasons because the ITCZ and the subtropical highs shift seasonally in latitude. Statement 3 is not accepted: the tropical monsoon climate gets its heavy rain from the monsoon circulation in the high-sun season, not from the ITCZ being near it for most of the year; it has a distinct dry season. So 1 and 2 only.

53. NDA 2023 (II)
Which one of the following climatic regions of the world have a typical characteristic of seasonal reversal of wind?
Answer and solution

Answer: (d) Monsoon Climate

Method. monsoon climate

The seasonal reversal of wind direction (summer onshore, winter offshore) is the defining feature of the monsoon climate. The British type and the Mediterranean climate are controlled by westerlies and the subtropical high; they have no such reversal.

54. NDA 2019 (II)
According to the Köppen climatic classification, the letter code Cfa denotes
Answer and solution

Answer: (b) Humid subtropical climate.

Method. Koppen letter codes

In Koppen's scheme C is mild mid-latitude, f means no dry season, a means hot summer: Cfa is the humid subtropical climate. Tropical wet is Af, tundra is ET, tropical wet and dry is Aw.

55. NDA 2018 (II)
Match List-I with List-II and select the correct answer using the code given below the Lists:
List-I (Koppen's Climatic Type)
A. Tropical wet
B. Mid-latitude desert
C. Mediterranean
D. Humid continental
List-II (Letter Code)
1. Af
2. Cs
3. Df
4. BWk
Code:
A B C D
Answer and solution

Answer: (a) 1 4 2 3

Method. Koppen climate codes

Tropical wet is Af (A-1); mid-latitude desert is BWk (B-4); Mediterranean is Cs (C-2); humid continental is Df (D-3). Code 1 4 2 3 is option (a).

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