Question

Which one of the following causes sediment movement parallel to shoreline in the coastal area?

• A. Longshore current
• B. Rip current
• C. Backwash
• D. Edge wave

Answer 1

The Correct Option is A

The question asks which factor causes sediment movement parallel to the shoreline in a coastal area. Let's analyze the given options:

1. Longshore current: This is a water current that moves parallel to the shore. It is created by waves that approach the shore at an angle, causing sediments to be transported along the coast. This is known as longshore drift, and it effectively moves sediments parallel to the shoreline, reshaping the coast over time.
2. Rip current: Unlike longshore currents, rip currents move perpendicularly from the shore, pulling water and sediments away from the coast into deeper water. They do not facilitate sediment movement parallel to the shoreline.
3. Backwash: This is the water that flows back into the sea after a wave has broken on the shore. It generally moves sediments perpendicular to the shoreline, either inward or outward, not parallel.
4. Edge wave: These are stationary waves that run along the coast and are perpendicular to the incoming waves. They have a limited role in sediment transport parallel to the shore.

Based on the above analysis, the correct answer is Longshore current, as it is responsible for transporting sediments parallel to the shoreline through the mechanism known as longshore drift.