Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Tides indicate the regular and periodic rise and fall in sea level.
Reason (R): Tides are caused by the gravitational pull of moon and earth.
In the light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Remember that while the Sun is much larger than the Moon, the Moon is much closer to the Earth.
Because gravitational tidal force is inversely proportional to the cube of the distance, the Moon's tide-generating force is about 2.17 times stronger than the Sun's.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
This question is in Assertion-Reason format and is based on physical geography and oceanography.
It tests our fundamental understanding of ocean tides, how they are defined, and the primary astronomical forces responsible for generating them.

Step 2: Detailed Explanation:

• Analyze Assertion (A):
Tides are indeed the periodic, regular rise and fall of the ocean's water level.
This phenomenon occurs once or twice a day, depending on the location on the Earth's surface, and is highly predictable.
Therefore, Assertion (A) is scientifically correct.

• Analyze Reason (R):
The primary forces that cause tides are the gravitational forces exerted by the Moon and the Sun on the Earth's oceans, combined with the rotation of the Earth.
Specifically, the differential gravitational pull of the Moon on different parts of the Earth creates a tidal bulge on both the near and far sides of the Earth.
Therefore, the statement that tides are caused by the gravitational pull of the Moon and the Earth (as a system) is correct.

• Verify if R is the Correct Explanation of A:
The regular and periodic rise and fall of sea levels (tides) is directly explained by these gravitational interactions.
As the Earth rotates through these gravitational bulges, different coastal locations experience high and low tides.
Thus, Reason (R) is the correct physical explanation for Assertion (A).

Step 3: Final Answer:
Both (A) and (R) are correct, and (R) is the correct explanation of (A).
Therefore, the correct choice is option (A).