Which one of the following do not influence the ocean currents ?
- A.Heating by solar energy
- B.Wind
- C.Gravitational pull by Sun and Moon
- D.Coriolis force
Correct answer
Explanation
The correct answer is C, Gravitational pull by Sun and Moon. The pull of the Sun and Moon raises the tides, the regular rise and fall of the sea, but it is not counted among the forces that drive ocean currents.
Ocean currents are steady, large-scale movements of water in a fixed direction. Their main drivers are the heating of the ocean by the Sun, which makes water near the equator expand and stand slightly higher; the planetary winds, which drag the surface water along; gravity, which pulls the higher water downslope; and the Coriolis force, which deflects the moving water to the right in the Northern Hemisphere and to the left in the Southern. Differences in temperature and salinity also cause density currents in the deep ocean.
Option A is wrong because solar heating starts the movement of water from the equator. Option B is wrong because wind is the chief force behind surface currents. Option D is wrong because the Coriolis force shapes the circular gyres of the oceans.
Exam tip: Sun and Moon make tides; Sun, wind, gravity and Coriolis make currents.
Practice Questions
View allWhich one among the following is the northernmost geographical location ?
- A.New Delhi
- B.Kathmandu
- C.Thimphu
- D.Dhaka
Show answer
New Delhi lies at about 28.6° N, a little north of both Kathmandu and Thimphu, even though Nepal and Bhutan lie to the north of most of India.
Read the full explanation →Which of the following is/are the applied forces in mechanical weathering process? 1. Gravitational force 2. Expansion force 3. Force due to water pressure Select the answer using the code given below :
- A.1 only
- B.1 and 2 only
- C.2 and 3 only
- D.1, 2 and 3
Show answer
Mechanical (physical) weathering breaks rocks without changing their chemistry, and all three forces drive it. Gravitational forces act as overburden pressure, load and shearing stress on rocks.
Read the full explanation →According to the Census 2011, the density of population in which one among the following States is the lowest ?
- A.Sikkim
- B.Nagaland
- C.Manipur
- D.Mizoram
Show answer
Census 2011 recorded about 52 persons per sq km in Mizoram, the lowest of the four states given. Mizoram is a hilly, heavily forested state with a small population of about 11 lakh, which keeps its density low.
Read the full explanation →Consider the following statements : 1. The Earth's magnetic field has reversed every few hundred thousand years. 2. When the Earth was created more than 4000 million years ago, there was 54% oxygen and no carbon dioxide. 3. When living organisms originated, they modified the early atmosphere of the Earth. Which of the statements given above is/are correct ?
- A.1 only
- B.2 and 3 only
- C.1 and 3 only
- D.1, 2 and 3
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The magnetic field has flipped many times and life changed the early air, but the young Earth had almost no free oxygen.
Read the full explanation →With reference to the current trends in the cultivation of sugarcane in India, consider the following statements : 1. A substantial saving in seed material is made when 'bud chip settlings' are raised in a nursery and transplanted in the main field. 2. When direct planting of setts is done, the germination percentage is better with single-budded setts as compared to setts with many buds. 3. If bad weather conditions prevail when setts are directly planted, single-budded setts have better survival as compared to large setts. 4. Sugarcane can be cultivated using settlings prepared from tissue culture. Which of the statements given above is/are correct?
- A.1 and 2 only
- B.3 only
- C.1 and 4 only
- D.2, 3 and 4 only
Show answer
Bud chip nurseries save seed cane and tissue-culture settlings are used, but single-bud setts do worse than larger setts when planted directly.
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