The 'time of tide' is determined by which of the following motions of earth and moon ? Select the correct answer from the codes given below :
(a) Earth's rotation
(b) Earth's revolution
(c) Moon's rotation
(d) Moon's revolution
Codes :

Question

The 'time of tide' is determined by which of the following motions of earth and moon ? Select the correct answer from the codes given below : 
(a) Earth's rotation 
(b) Earth's revolution 
(c) Moon's rotation 
(d) Moon's revolution
Codes :

Accepted Answer

The 'time of tide' is primarily determined by the Earth's rotation and the Moon's revolution. Here's why Option 3 (a and d) is the correct answer:

*   **Earth's Rotation (a):** The Earth's rotation on its axis is the fundamental reason why a given point on Earth experiences high and low tides approximately twice a day. As the Earth rotates, different locations pass under the Moon's gravitational influence, leading to the cyclical rise and fall of sea levels. Without Earth's rotation, there would be no daily tidal cycle.

*   **Moon's Revolution (d):** The Moon's revolution around the Earth is crucial because the Moon's gravitational pull is the primary force responsible for creating tides. As the Moon orbits the Earth, the location of the tidal bulge (the area of high tide) changes. The Moon's revolution also affects the timing of tides; the lunar day (the time it takes for a specific point on Earth to return to the same position relative to the Moon) is longer than a solar day, which is why tides occur about 50 minutes later each day.

Now, let's explain why the other options are incorrect:

*   **Option 1 (a, b, c, and d):** While Earth's rotation and Moon's revolution are directly related to the timing of tides, Earth's revolution around the sun and Moon's rotation on its axis have a less direct and significant impact on the *time* of tides. Earth's revolution around the sun influences the *magnitude* of tides (spring and neap tides), but not the basic timing. The Moon's rotation is tidally locked with Earth, meaning its rotation period is the same as its orbital period, and while this is interesting, it doesn't directly determine the *time* of tides.

*   **Option 2 (b and d):** While the Moon's revolution (d) is a key factor, Earth's revolution (b) around the sun primarily influences the *magnitude* of tides (spring and neap tides) due to the alignment of the sun, Earth, and moon. It doesn't dictate the fundamental daily timing of high and low tides, which is primarily driven by Earth's rotation.

*   **Option 4 (a and c):** While Earth's rotation (a) is a key factor, the Moon's rotation (c) on its axis is tidally locked with Earth, meaning its rotation period is the same as its orbital period, and while this is interesting, it doesn't directly determine the *time* of tides. The Moon's revolution around the Earth is the primary force responsible for creating tides.

Therefore, Option 3 (a and d) is the most accurate answer because it correctly identifies Earth's rotation and the Moon's revolution as the primary factors determining the 'time of tide'.