[Mission 2022] QUIZ – 2020: INSIGHTS STATIC QUIZ , 26 October 2021 – Geography – INSIGHTSIAS

Solution: a)

The sub-polar low-pressure belts extend between 45°N and the Arctic Circle (66°30′ N) in the northern hemisphere and between 45°S and the Antarctic Circle (66°30′ S) in the southern hemisphere. They are known as the North sub-polar low and the South sub-polar low-pressure belts respectively. Winds coming from the sub-tropical and the polar high belts converge here to produce cyclonic storms or low-pressure conditions.

A low-pressure area, is a region where the atmospheric pressure is lower than that of a surrounding area. A low-pressure system develops when warm and moist air rises from the Earth’s surface and the air in the surrounding area rushes in to fill the empty space created by this rising air, thus forming a heavy inflow of wind.

Solution: b)

The directions of prevailing winds are largely determined by the Coriolis effect.

In northern hemisphere, wind deflects clockwise, while in southern hemisphere, wind deflects anti-clockwise.

Solution: b)

Air pressure is defined as the pressure exerted by the weight of air on the earth’s surface. As we go up the layers of atmosphere, the pressure falls rapidly.

In areas where temperature is high the air gets heated and rises. This creates a low-pressure area. Low pressure is associated with cloudy skies and wet weather.

• In areas having lower temperature, the air is cold. It is therefore heavy.
• Heavy air sinks and creates a high pressure area. High pressure is associated with clear and sunny skies.
• The air always moves from high pressure areas to low pressure areas.

Solution: c)

Atmospheric pressure is caused by the weight of the atmosphere pushing down on itself and on the surface below it.

Atmospheric pressure decreases with height above the surface of a planet because there is less total mass in the atmosphere above a reference point as the height of the reference point increases.

This is explained by the heaviness of air closer to the earth.  Air is heaviest at sea level because the air molecules are pressed together due to gravity.

Solution: c)

The ITCZ is a zone of convergence at the thermal equator where the trade winds meet and it is a zone where air tends to ascend. It is a low-pressure belt and migrates with the changing position of the thermal equator.

The thermal equator receives the most intense heat from the Sun. Around 20th June each year the Sun is overhead at 23½º North, the Tropic of Cancer. Around 20th December the Sun is overhead at 23½º South, the Tropic of Capricorn.

The movement of the thermal equator shifts the belts of planetary winds and pressure systems to the north and to the south annually.