The average salinity of ocean water is about:
- A.15 parts per thousand
- B.25 parts per thousand
- C.35 parts per thousand
- D.45 parts per thousand
Correct answer
Explanation
The correct answer is C, about 35 parts per thousand, which means roughly thirty-five grams of dissolved salt in every kilogram of sea water. Sodium chloride makes up most of it, with magnesium, calcium and potassium salts making up the rest. Salinity varies with evaporation, rainfall, river inflow and the melting or freezing of ice, so the figure is an average rather than a fixed value.
Option A, 15 parts per thousand, is closer to brackish water in an estuary or to the low-salinity Baltic Sea, where many rivers pour in fresh water. Option B, 25 parts per thousand, is still well below the open ocean figure. Option D, 45 parts per thousand, is higher than any open ocean value; even the Red Sea, the most saline of the open seas, stays near the low forties, and only enclosed lakes such as the Dead Sea go far above that.
Read the full article: Oceans and Ocean Currents: Tides, Salinity and PYQs
Practice Questions
View allWhich of the following ocean currents is associated with the Indian Ocean?
- A.Florida current
- B.Canary current
- C.Agulhas current
- D.Kurile current
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It is a warm current of the Indian Ocean that flows southward along the eastern coast of southern Africa, carrying tropical water towards the Cape before most of it turns back into the Indian Ocean.
Read the full explanation →El Nino is a name given to the periodic development of a warm ocean current along the coast of _______.
- A.Columbia
- B.Peru
- C.Chile
- D.Bolivia
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El Nino, Spanish for the child, is the warm surface water that appears off the coast of Peru and Ecuador around Christmas in some years, replacing the normally cold Peru or Humboldt current.
Read the full explanation →With which of the following oceans would you associate the 'Ring of Fire'?
- A.Pacific
- B.Indian
- C.Atlantic
- D.Arctic
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The Ring of Fire is a horseshoe-shaped belt running around the rim of the Pacific Ocean, from the Andes up the west coast of the Americas, across the Aleutians and down through Japan, the Philippines and Indonesia to New Zealand.
Read the full explanation →The percentage of earth's water found in the oceans is ______.
- A.94 percent
- B.97.2 percent
- C.90.2 percent
- D.92.2 percent
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Textbooks describing the distribution of water on earth give about 97.2 per cent as ocean water, roughly 2 per cent locked in ice caps and glaciers, and well under 1 per cent as groundwater, lakes, rivers, soil moisture and water vapour together.
Read the full explanation →Spring tides, the highest tides of the month, occur when:
- A.The sun, the earth and the moon are in a straight line
- B.The sun and the moon are at right angles with respect to the earth
- C.The moon is farthest from the earth
- D.The season of spring begins in the northern hemisphere
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Spring tides occur at new moon and at full moon, when the sun, the earth and the moon lie in a straight line, a position called syzygy.
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