Question

In deep ocean, Tsunamis have:

• A. Very long wave length and very low amplitude
• B. Long wave length and low amplitude
• C. Very small wave length and low amplitude
• D. Small wave length and very high amplitude

Hint:

In deep ocean, tsunami waves have very long wavelength and very low amplitude. Near the coast, the wave height increases and becomes dangerous.

Answer 1

The Correct Option is A

Concept: Tsunami waves behave differently in deep ocean and near the coast. In deep ocean, they travel very fast with very long wavelength and very small height.

Step 1: Understanding tsunami behaviour in deep ocean.
In the deep ocean, tsunami waves are not very high. Their amplitude is very low, so ships may not even notice them. \[ \text{Deep ocean tsunami} \Rightarrow \text{Very long wavelength + Very low amplitude} \]

Step 2: Understanding wavelength and amplitude.
Wavelength means the distance between two consecutive crests.
Amplitude means the height of the wave from the mean water level.

Step 3: Why tsunami becomes dangerous near coast.
When a tsunami enters shallow water near the coast, its speed decreases and wave height increases. This process is called shoaling. \[ \text{Near coast} \Rightarrow \text{Speed decreases and height increases} \] Therefore, in deep ocean, tsunamis have very long wavelength and very low amplitude.