Option 1 : (A) only
Correct Answer: (A) only.
Sea Waves A moving ridge or swell of water occurring close to the surface of the sea is characterized by oscillating and rising and falling movements, often as a result of the frictional drag of the wind. Ocean waves (swell) are formed by transferring energy from the motion of atmospheric wind to the ocean surface and releasing a certain amount of energy to the shoreline, causing erosion and accretion of coastal landforms on a long-term scale.
- The mechanism of the origin of sea waves is commonly believed that waves are generated due to friction on the water surface caused by blowing winds.
- The Height of winds generated by sea waves depends on
- (I) Wind Speed,
- (II) The duration of wind from one direction, and
- (III) The extent of fetch.
- Wave height is an indicator of wave energy.
- The amount of energy in a wave depends on its height and wavelength as well as the distance over which it breaks.
- Wave height is affected by wind speed, wind duration (or how long the wind blows), and fetch, which is the distance over water that the wind blows in a single direction.
- If wind speed is slow, only small waves result, regardless of wind duration or fetch.
- Because deep-water waves do not interact with the ocean bottom as they travel, their speed is independent of the water depth.
- But as waves enter shallow water, interaction with the bottom alters the waves.
- Wave speed decreases, the wavelength shortens, and wave height increases.
- In open seawater, there is no friction which is why wind travels easily and waves height is affected.
- Wave Period: The time it takes for two successive crests (one wavelength) to pass a specified point.
- Wave Frequency - The number of waves that pass a particular point in a given time period.
- There is an inverse relationship between the wavelength and wave frequency.
- Wave velocity is directly related to wavelength.