Which of the following is not a practical use of Tides? 1. Navigation 2. Desilting and pollution removal from water 3. Electricity Generation 4. Development of Coral Reefs
Tides are caused by the earth, moon, and sun's gravitational pull and their position . Tidal flows are of great importance in navigation and help the navigators and fishermen plan their activities. Hence, Statement 1 is correct. Harbors near rivers and within estuaries having shallow ‘bars’ at the entrance prevent ships and boats from entering into the harbor. Tides are also helpful in desilting the sediments and in removing polluted water from river estuaries. Hence, Statement 2 is correct. Tides are used to generate electrical power as its mechanical energy is used to drive a turbine that produces electricity. Hence, Statement 3 is correct. Tides vary in their frequency, direction, and movement from place to place and also from time to time. Tides may be grouped into various types based on their frequency of occurrence in one day or based on their height. Tides based on the Sun, Moon, and the Earth Positions. The height of rising water varies depending upon the position of the sun and moon concerning the earth. The ‘tide-generating’ force is the difference between the gravitational attraction of the moon and the centrifugal force. The shape of bays and estuaries along a coastline can also magnify the intensity of tides . Funnel-shaped bays greatly change tidal magnitudes . It is not as such useful in the Development of Coral Reefs. Hence, Statement 4 is incorrect.