The correct option is (c).
Explanation
Tides refer to the periodical rise and fall of the sea level, occurring once or twice a day, primarily due to the attraction of the sun and the moon. The movement of water caused by meteorological effects (winds and atmospheric pressure changes) are called surges, which are distinct from tides.
Statement-wise Analysis
- Statement 1 is Correct: The strong gravitational pull exerted by the sun and the moon on the earth’s surface is the primary cause of tides. While the moon's gravitational force is the dominant factor due to its proximity to Earth, the sun also plays a significant role.
- Statement 2 is Incorrect: High tides generally help in navigation rather than making it difficult. They raise the water level close to the shores, which enables ships to enter harbours safely. This is particularly crucial for harbours located in shallow waters or estuaries (e.g., Kandla Port in India or the port of London on the Thames).
- Statement 3 is Correct: The rise and fall of water due to tides create a potential energy difference that can be harnessed to generate electricity. Tidal energy is a form of hydropower that converts the energy obtained from tides into useful forms of power, mainly electricity.
Key Takeaway: Tides are caused by the gravitational forces of the moon and sun. Economically, they are vital for navigation in shallow ports, desilting sediments in estuaries, and generating renewable tidal energy.