Previous Year Question
Which of the following statement is true?
Tide comes on the earth every day after exactly 12 hours 30 minutes.
Benguela current is a cold current of the pacific ocean.
Ocean salinity is maximum at the Tropic of Cancer and Capricorn.
If the sun, the earth and the moon are in a straight line then this situation is the situation of small tide.
Correct Answer: C
Detailed Solution
Surface salinity of the oceans is mainly influenced by the balance between evaporation and precipitation. In the subtropical regions, approximately between 20° and 30° north and south latitudes, evaporation is high while rainfall is comparatively low. Therefore, surface salinity is generally high in these regions. The question expresses this pattern as maximum salinity around the Tropics of Cancer and Capricorn.
Although temperatures are high in the equatorial region, heavy rainfall dilutes seawater, so salinity there is lower than in the subtropical belts. Salinity is also comparatively low in polar regions because evaporation is very low and melting ice adds freshwater.
Statement (a) is incorrect because in a normal semidiurnal tidal cycle, successive high tides occur approximately 12 hours and 25 minutes apart, not exactly 12 hours and 30 minutes.
Statement (b) is also incorrect. The Benguela Current is a cold current, but it flows in the South Atlantic Ocean, not in the Pacific Ocean.
Statement (d) is incorrect because when the Sun, Earth and Moon are nearly aligned, their gravitational effects combine to produce a Spring Tide, which has a larger tidal range. A Neap Tide occurs when the Sun and Moon are approximately at right angles relative to the Earth.