Question

The periodic rise and fall of water level in the ocean is called _______.
(A) waves
(B) tides
(C) water current
(D) turbidity currents

Answer 1

Hint: It is often used as an energy source to harness and thereby produce electricity.This is to be predicted for travelling across oceans in order to decide channels of navigation.

Complete answer:The periodic rise and fall of water level in the ocean are termed as tides. These ocean tides are formed when the ocean will respond to actions such as rotation of the earth and pull of gravitational forces of the moon. These factors which create tides are termed as tide constituents. Tide constituents also act in the land too, but unlike the land on the earth the ocean is more flexible, this causes the ocean to be more vulnerable. Among the tidal constituents, the gravitational pull of the moon is more influential in the formation of tides as the moon is more proximate to earth than the sun.

Option (A): The ocean waves are the process of exchange of energy taking place in water in a circular manner. The waves are not caused by the gravitational pull of Earth's rotation. Instead, it is caused more likely by the friction formed between earth surface and wind. This option is incorrect.

Option (B): The natural rise and fall of the ocean’s waters are tides. It is at high tide when the water has risen to its highest level. When the water falls to the lowest level, it is at low tide. This option is correct.

Option (C): In the case of water current, it is simply the uninterrupted, directional movement of water, due to the action of certain forces on it. This option is incorrect.

Option (D): Turbidity currents are rapid, downhill flowing of water formed by increased density due to high quantities of sediment. Earthquakes, collapsing slopes, and other geological irregularities can lead to turbidity currents. This option is incorrect.

Thus the option (B) is correct.

Note: Even though rip tide has a tide in it, it is actually an ocean current. A rip tide is an ocean current which takes water back to the open ocean from the shore. An ebb tide refers to the flow of water from high tide to low tide.