The correct option is 2 and 3 only
Explanation
The magnitude (height) of tides is primarily generated by the gravitational pull of the moon and the sun. However, the actual observed height at any specific location is significantly modified by local terrestrial and bathymetric factors, such as the configuration of the coastline and the depth of the ocean.
Statement-wise Analysis
- Statement 1 is Incorrect. The shape of bays and estuaries has a significant influence on the magnitude of tides. Funnel-shaped bays (e.g., the Bay of Fundy) constrict the incoming tidal wave, forcing water to pile up and creating extremely high tidal ranges. The statement claims it has "no influence," which is factually wrong.
- Statement 2 is Correct. The presence of wide continental shelves influences tidal height. As the tidal wave moves from the deep ocean onto the shallow continental shelf, the speed of the wave decreases, causing the water to pile up and increasing the tidal height.
- Statement 3 is Correct. The presence of mid-oceanic islands influences the observed tidal magnitude. In the open ocean, tidal bulges are generally very low (often less than 1 meter) because the water is not constricted. Consequently, tides observed at mid-oceanic islands are typically low in magnitude compared to those along continental margins.
Key Takeaway
Local Modification of Tides: While astronomical forces generate tides, their magnitude is determined by local factors:
bays and estuaries magnify tides through funneling,
continental shelves increase height due to shallow depths, and
mid-oceanic islands (open ocean) experience low tidal ranges.