Question 1

A cyclone is generally associated with which type of pressure centre?

Accepted Answer

A low-pressure centre A cyclone is a rotating weather system centred on relatively low atmospheric pressure. Air generally moves inward toward the low-pressure centre and rises because of surface convergence. Rising air cools, often producing cloud, strong winds, and precipitation. In contrast, an anticyclone is centred on high pressure, with air tending to descend and spread outward. Therefore option A is the only correct answer.

Question 2

In which condition will cyclonic weather be considered more likely?

Accepted Answer

A closed low-pressure centre with surface convergence A cyclone is an organized low-pressure system in which air generally converges near the surface and rises. Rising air can cool, condense, and support clouds, precipitation, and unsettled weather. A closed high, subsiding air, widely spaced isobars, and polar high pressure are associated more with anticyclonic or stable conditions. Hence option A is correct.

Question 3

Why is cloud formation less likely in an anticyclone?

Accepted Answer

Air sinks, warms, and becomes stable An anticyclone is a high-pressure system characterized by descending air. As the air sinks, it is compressed and warms adiabatically, lowering its relative humidity and discouraging condensation. Subsidence also suppresses vertical cloud development, so skies are often clearer and weather more stable. Therefore, option B correctly explains the reduced likelihood of cloud formation.

Question 4

Which system is especially affected by the seasonal shifting of pressure belts?

Accepted Answer

The monsoon wind system Pressure belts shift northward and southward with the apparent seasonal movement of the Sun and the changing pattern of land and sea heating. These shifts alter the pressure gradient between continents and oceans, changing the direction and strength of seasonal winds. The monsoon is therefore closely linked with the seasonal migration of pressure belts. Hence, option B is correct.

Question 5

The polar front is most likely to form between which air masses?

Accepted Answer

Cold polar air and warm mid-latitude air A front is a boundary between air masses with different properties, especially temperature and density. The polar front develops in the subpolar belt where cold, dense polar air meets relatively warm air from the mid-latitudes. Their strong thermal contrast supports instability, frontal uplift, and the formation of temperate cyclones. It is therefore not a boundary between similar equatorial or subtropical air masses.

Question 6

Why do fronts form more often in subpolar regions?

Accepted Answer

Because warm westerlies and cold polar winds meet there The subpolar zone, near the polar front, is a meeting region for relatively warm, moist air carried poleward by the westerlies and cold, dense air moving equatorward as polar easterlies. Because these air masses differ strongly in temperature and density, a sharp boundary develops between them. This boundary supports frontal uplift, cyclogenesis, cloud formation, and unsettled weather.

Question 7

Cyclonic weather activity in mid-latitudes is most closely linked with which pressure and wind arrangement?

Accepted Answer

Subpolar low pressure and belt of westerlies Mid-latitude cyclones are strongly associated with the subpolar low-pressure belt, especially along the polar front where contrasting cold polar and warmer subtropical air masses meet. The prevailing westerlies transport and steer these systems, producing changing winds, clouds, fronts, and precipitation.

Question 8

What is meant by an air mass?

Accepted Answer

A large body of air with similar temperature and humidity An air mass is a large body of air that develops fairly uniform temperature and moisture characteristics over an extensive source region. It acquires these properties by remaining over the region for sufficient time. Its origin may be land or ocean, so options C and D are too restrictive.

Question 9

What type of source region is most suitable for air-mass formation?

Accepted Answer

A broad, uniform, and relatively calm surface An ideal source region is broad and uniform, such as a large ocean, snow-covered plain, or extensive desert. When air remains over such a surface for a considerable time, it acquires fairly uniform temperature and moisture. Calm conditions reduce mixing with contrasting air and help the air mass develop.

Question 10

What is the usual characteristic of a continental polar air mass?

Accepted Answer

Cold and dry A continental polar air mass forms over high-latitude land surfaces. The cold source region gives it a low temperature, while land generally supplies much less moisture than an ocean. It is therefore characteristically cold and dry, although local weather can modify its properties after it moves away from the source.

Question 11

What is a maritime tropical air mass usually like?

Accepted Answer

Warm and humid A maritime tropical air mass develops over warm tropical or subtropical oceans. The warm water supplies heat, while evaporation adds abundant water vapour to the air. Consequently, this air mass is generally warm and humid. When lifted, it can support cloud formation and substantial rainfall.

Question 12

What is the meeting zone of two different air masses called?

Accepted Answer

A front A front is a boundary or transition zone where two air masses with contrasting temperature and moisture characteristics meet. Because the air masses interact there, fronts are often associated with clouds, precipitation, and changes in wind or temperature. An isobar instead joins places with equal atmospheric pressure.

Question 13

Why do heavy showers and thunderstorms often occur along a cold front?

Accepted Answer

Cold, dense air forces warm, moist air to rise rapidly At a cold front, advancing dense cold air pushes beneath warmer, often moist air and lifts it sharply. The rising air expands and cools, causing condensation and rapid development of cumuliform or cumulonimbus clouds. These vertically developed clouds can produce intense showers, lightning, and thunder. Warm air does not sink at the front.

Question 14

Why can rainfall along a warm front continue for a long time?

Accepted Answer

Warm air slowly rises over cold air At a warm front, the advancing warm air is less dense and gradually overruns the retreating cold air along a gentle slope. This slow, widespread uplift cools the air and produces layered clouds such as nimbostratus. The broad cloud shield can bring steady, light or moderate precipitation over an extended period and area.

Question 15

What is the main feature of a stationary front?

Accepted Answer

The boundary between two air masses remains nearly fixed A stationary front forms when neither of the two opposing air masses has enough force to displace the other significantly. The boundary therefore remains nearly in place for some time. Persistent cloudiness, light or moderate precipitation, and prolonged unsettled weather may occur along it, although the exact weather depends on moisture and stability.

Question 16

What is the basic pressure pattern of a cyclone?

Accepted Answer

Low pressure at the centre and relatively higher pressure around it A cyclone is an atmospheric system organised around a relatively low-pressure centre, with comparatively higher pressure in the surrounding region. The pressure-gradient force drives air inward, while the Coriolis force deflects the moving air and produces rotation. Rising air near the centre commonly leads to cloud formation and unsettled weather. Option B mentions only the centre and is therefore incomplete; option D states the complete basic pressure pattern.

Question 17

What is the usual direction of cyclonic winds in the Northern Hemisphere?

Accepted Answer

Anticlockwise and inward In the Northern Hemisphere, air moving toward a low-pressure centre is deflected to the right by the Coriolis effect. The combined action of the pressure-gradient force and this deflection produces an inward, anticlockwise circulation around a cyclone. The wind direction is not simply eastward or vertical. In the Southern Hemisphere the corresponding cyclonic circulation is generally clockwise.

Question 18

How does a cyclone usually rotate in the Southern Hemisphere?

Accepted Answer

Clockwise A cyclone is a low-pressure system with converging winds. In the Southern Hemisphere, the Coriolis effect deflects moving air to the left. This deflection turns the inward-moving air into a generally clockwise circulation around the low-pressure centre. The direction is opposite to the anticlockwise circulation of Northern Hemisphere cyclones, although local winds can be influenced by friction and terrain.

Question 19

Mid-latitude cyclones are closely associated with which feature?

Accepted Answer

Fronts Mid-latitude, or extratropical, cyclones usually develop where contrasting warm and cold air masses meet. The boundary between these air masses is called a front. Disturbances along the front can deepen into a cyclone, producing cloud bands, precipitation, and changing winds. Monsoon breaks, mirages, and ocean tides are not the defining atmospheric structures responsible for the formation of mid-latitude cyclones.

Question 20

What is called the eye of a cyclone?

Accepted Answer

Relatively calm and clearer central part The eye is the relatively calm central region of a mature tropical cyclone. Air in this area often descends, so skies may become clearer and winds are much lighter than in the surrounding eyewall. The eyewall, not the eye, contains the strongest winds, heaviest rain, and most intense thunderstorms. A cyclone does not have an area without pressure; every part of the atmosphere has pressure.

Question 21

What is the main reason for cloud formation along a front?

Accepted Answer

Rising and cooling of warm air A front is a boundary between contrasting air masses. Because warm air is less dense, it is forced to rise over denser cold air, or is lifted as the front advances. Rising air expands and cools, reducing its capacity to hold water vapour. When saturation is reached, condensation forms cloud droplets or ice crystals. Therefore, uplift followed by cooling is the main reason for frontal cloud formation.

Question 22

What is the usual effect on temperature after a cold front passes?

Accepted Answer

Temperature falls A cold front forms when a colder, denser air mass advances and pushes beneath warmer air. After the front passes, the colder air occupies the area, so the surface temperature usually falls, often fairly quickly. Wind direction, cloud cover, and pressure may also change, and brief precipitation can occur near the boundary. The fall is a usual weather tendency, not necessarily a permanent or identical change everywhere.

Question 23

Which type of clouds may appear first before the arrival of a warm front?

Accepted Answer

High, thin clouds A warm front has a gently advancing warm air mass that rises over cooler air along a broad slope. Because the lifting begins far ahead of the surface boundary, the first clouds commonly observed are high, thin cirrus or cirrostratus clouds. As the front approaches, clouds generally become lower and thicker, and precipitation may develop. Thus high, thin clouds are an early warning sign of an approaching warm front.

Question 24

What may happen when an air mass moves away from its source region over a new surface?

Accepted Answer

Its properties may be modified An air mass acquires its initial temperature and moisture characteristics over a broad source region, such as an ocean, desert, or snow-covered land. After it travels over a different surface, it exchanges heat and moisture with that surface and mixes with surrounding air. Consequently, its temperature, humidity, stability, and sometimes cloud-forming potential may change. It is modified, not automatically destroyed or reduced to zero pressure.

Question 25

What is a continental tropical air mass generally like?

Accepted Answer

Hot and dry A continental tropical air mass develops over hot tropical land surfaces, especially deserts and semi-arid interiors. Because it forms over land, it contains comparatively little moisture, while strong solar heating gives it a high temperature. Therefore, its characteristic combination is hot and dry, making option A correct.

Air masses, fronts, and cyclones

Practice questions

01 A cyclone is generally associated with which type of pressure centre?

02 In which condition will cyclonic weather be considered more likely?

03 Why is cloud formation less likely in an anticyclone?

04 Which system is especially affected by the seasonal shifting of pressure belts?

05 The polar front is most likely to form between which air masses?

06 Why do fronts form more often in subpolar regions?

07 Cyclonic weather activity in mid-latitudes is most closely linked with which pressure and wind arrangement?

08 What is meant by an air mass?

09 What type of source region is most suitable for air-mass formation?

10 What is the usual characteristic of a continental polar air mass?

11 What is a maritime tropical air mass usually like?

12 What is the meeting zone of two different air masses called?

13 Why do heavy showers and thunderstorms often occur along a cold front?

14 Why can rainfall along a warm front continue for a long time?

15 What is the main feature of a stationary front?

16 What is the basic pressure pattern of a cyclone?

17 What is the usual direction of cyclonic winds in the Northern Hemisphere?

18 How does a cyclone usually rotate in the Southern Hemisphere?

19 Mid-latitude cyclones are closely associated with which feature?

20 What is called the eye of a cyclone?

21 What is the main reason for cloud formation along a front?

22 What is the usual effect on temperature after a cold front passes?

23 Which type of clouds may appear first before the arrival of a warm front?

24 What may happen when an air mass moves away from its source region over a new surface?

25 What is a continental tropical air mass generally like?

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