hydrosphere & oceanography section 1 MCQ Questions & Answers Detailed Explanation

Answer: (b)

Tide-generating forces (TGF) are a result of the gravitational attraction between the earth, the sun, and the moon and the centrifugal force due to the relative motions of the moon around the earth, and the earth around the sun.

While these forces exactly balance on average, the local mismatch at the earth's surface creates a horizontal force directed towards the surface points closest and farthest from the moon.

Answer: (b)

The horizontal distribution of temperature of ocean water is largely affected by ocean current, prevailing winds and latitudes.

Answer: (b)

Answer: (d)

Tsunamis have a small amplitude (wave height) offshore, and a very long wavelength (often hundreds of kilometres long, whereas normal ocean waves have a wavelength of only 30 or 40 metres), which is why they generally pass unnoticed at sea, forming only a slight swell usually about 300 millimetres above the normal sea surface. They grow in height when they reach shallower water or the coast.

Answer: (c)

The Humboldt Current, also known as the Peru Current, is a cold, low-salinity ocean current that flows north-westward along the west coast of South America from the southern tip of Chile to northern Peru.

It is an eastern boundary current flowing in the direction of the equator and can extend 1,000 kilometres offshore. The Humboldt Current Large Marine Ecosystem (LME), named after the Prussian naturalist Alexander von Humboldt, is one of the major upwelling systems of the world, supporting an extraordinary abundance of marine life.

Upwelling occurs off Peru year-round but off Chile only during the spring and summer, because of the displacement of the subtropical centre of high pressure during the summer.

Answer: (d)