Which one of the following can be said to be essentially related to 'Polar Front Theory' ?
- A.Anticyclone
- B.Tropical Cyclone
- C.Temperate Cyclone
- D.Inter Tropical Convergence
Correct answer
Explanation
The correct answer is C, Temperate Cyclone. The Polar Front Theory explains how temperate or extra-tropical cyclones are born and grow.
The theory was put forward by the Norwegian meteorologists Vilhelm and Jacob Bjerknes around the end of the First World War. Along the polar front, cold dry polar air meets warm moist tropical air in the middle latitudes. A wave forms on this front, warm air rises over the cold air, pressure falls and an anticlockwise circulation in the northern hemisphere develops, with a warm front and a cold front. When the cold front overtakes the warm front, an occluded front forms and the cyclone dies out.
A is wrong because an anticyclone is a high-pressure system of sinking air, not born on a front. B is wrong because tropical cyclones form over warm seas without fronts. D is wrong because the Inter Tropical Convergence Zone is a low-pressure belt near the equator where the trade winds meet.
Exam tip: Polar Front Theory, Bjerknes, temperate cyclone; warm front, cold front, then occlusion.
Practice Questions
View allWhich one of the following is not a form of condensation?
- A.Dew
- B.Fog
- C.Frost
- D.Sleet
Show answer
Sleet is a form of precipitation, frozen raindrops or a mix of rain and snow that falls from clouds, not a form of condensation.
Read the full explanation →Which one of the following cities was the first to attain the status of a 'megacity'?
- A.London
- B.Paris
- C.New York
- D.Washington
Show answer
New York, with its urban agglomeration, became the first city to cross a population of 10 million, around 1950. A megacity is an urban agglomeration with more than 10 million people, the threshold used by the United Nations.
Read the full explanation →The shortest day length that occurs in the Northern hemisphere is on
- A.21st March
- B.23rd September
- C.22nd November
- D.22nd December
Show answer
On the winter solstice the Sun is overhead at the Tropic of Capricorn, so the Northern Hemisphere has its shortest day and longest night.
Read the full explanation →Which one of the following is likely to be the most prevalent form of weathering in hot-tropical desert areas?
- A.Mechanical
- B.Chemical
- C.Biological
- D.Leaching
Show answer
Hot deserts have a large daily range of temperature and very little moisture, so rocks break up physically rather than decay chemically.
Read the full explanation →Which of the following positions of Sun, Earth and Moon is/are suitable for Spring Tide ?
1. SYZYGY Conjunction
2. SYZYGY Opposition
3. Quadrature
Select the correct answer using the code given below:
- A.1 only
- B.2 only
- C.1 and 2
- D.1 and 3
Show answer
Spring tides occur whenever the Sun, the Earth and the Moon lie in a straight line, a position called syzygy, whether the Moon is on the same side as the Sun or the opposite side.
Read the full explanation →