The Earth's equatorial region bulges outward, but the Earth flattens slightly towards the polar regions due to the :
- A.Presence of a large oceanic mass in the southern hemisphere
- B.Earth's rotational force
- C.Earth's revolution
- D.Greater gravitational force at the equator
Correct answer
Explanation
The correct answer is B, Earth's rotational force. The spin of the Earth throws the equatorial belt outward, so the planet bulges at the equator and is flattened at the poles.
The Earth rotates once on its axis in about 24 hours. A point on the equator travels about 40,000 km in that time, while a point near a pole hardly moves, so the outward (centrifugal) effect of rotation is greatest at the equator. Over geological time this pushed material outward and gave the Earth the shape of an oblate spheroid, or geoid. The equatorial diameter is about 43 km longer than the polar diameter.
A is wrong because the oceans of the southern hemisphere do not shape the solid Earth this way. C is wrong because revolution around the Sun causes the seasons, not the bulge. D is wrong because gravity is actually slightly weaker at the equator, partly because of this bulge.
Exam tip: rotation causes day and night and the equatorial bulge; revolution causes the seasons.
Practice Questions
View allWhere is Hambantota Port located?
- A.Iran
- B.Sri Lanka
- C.Japan
- D.Pakistan
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Hambantota Port lies on the southern coast of Sri Lanka, close to the main shipping lanes of the Indian Ocean.
Read the full explanation →Which of the following statements is/are correct? 1. Himalayan rivers have their origin in the snow-covered areas, hence are dry in winter season. 2. Rivers of the Peninsular Plateau have reached maturity. 3. Himalayan rivers depict all the three stages of normal cycle of erosion. Select the correct answer using the code given below.
- A.2 only
- B.1 and 3 only
- C.2 and 3 only
- D.1, 2 and 3
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Himalayan rivers are perennial, so statement 1 is wrong, while statements 2 and 3 are correct. Himalayan rivers such as the Ganga, Indus and Brahmaputra rise from glaciers and snowfields and also get monsoon rain, so they flow all year round, including in winter.
Read the full explanation →Which of the following statements related to latitude are true? 1. Rainfall, temperature and vegetation vary with latitude. 2. The difference between the longest day and the shortest day increases with latitude. 3. Indira Point is located approximately at 6°45' N latitude. Select the correct answer using the code given below.
- A.1 and 2 only
- B.1 and 3 only
- C.2 and 3 only
- D.1, 2 and 3
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All three statements about latitude are true. Latitude decides how directly the Sun's rays strike a place, so temperature, rainfall and the type of vegetation change from the equator towards the poles, from hot, wet rainforests to cold tundra.
Read the full explanation →Which of the following lakes is/are situated in Ladakh? 1. Tso Kar 2. Pangong Tso 3. Tsomgo 4. Tso Moriri Select the correct answer using the code given below.
- A.1 only
- B.2 and 3
- C.1, 2 and 4
- D.2 and 4 only
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Tso Kar, Pangong Tso and Tso Moriri are high-altitude lakes of Ladakh, while Tsomgo lies in Sikkim. Pangong Tso, at about 4,350 metres, is a long, narrow lake that stretches from Ladakh into Tibet, and most of its length lies on the Chinese side.
Read the full explanation →Damanganga Reservoir Project with about 115 km of minor canals and distributaries is located in
- A.NCT
- B.Dadra and Nagar Haveli
- C.Puducherry
- D.Goa
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The Damanganga Reservoir Project is the main irrigation scheme of Dadra and Nagar Haveli, whose canal network of about 115 km of minor canals and distributaries serves the territory.
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