Easy MCQ +4 / -1 PYQ · JEE Mains 2023

Given below are two statements:

Statement I : Rotation of the earth shows effect on the value of acceleration due to gravity (g)

Statement II : The effect of rotation of the earth on the value of 'g' at the equator is minimum and that at the pole is maximum.

In the light of the above statements, choose the correct answer from the options given below

  1. A Statement I is false but statement II is true
  2. B Statement I is true but statement II is false Correct answer
  3. C Both Statement I and Statement II are true
  4. D Both Statement I and Statement II are false

Solution

<p>Let's analyze both statements:</p> <p><strong>Statement I:</strong> Rotation of the earth shows an effect on the value of acceleration due to gravity (g).</p> <p>This is <strong>true</strong>. The value of $ g $ is affected by the rotation of the Earth. The centripetal force due to the Earth's rotation causes a reduction in the perceived gravitational acceleration for objects on the surface. This effect is zero at the poles and increases towards the equator. The formula for the effective acceleration due to gravity at a latitude $ \theta $ is:</p> $g_{\text{effective}} = g - R\omega^2\cos^2(\theta)$ <p>where:</p> <ul> <li>$ g $ is the theoretical acceleration due to gravity without Earth's rotation,</li> <li>$ R $ is the radius of the Earth,</li> <li>$ \omega $ is the angular velocity of the Earth's rotation, and</li> <li>$ \theta $ is the latitude.</li> </ul> <p><strong>Statement II:</strong> The effect of rotation of the earth on the value of 'g' at the equator is minimum and that at the pole is maximum.</p> <p>This is <strong>false</strong>. For clarification, the effect of the Earth's rotation on the value of $ g $ is maximum at the equator and minimum at the poles. At the equator, the centrifugal force is highest because of the maximum velocity due to Earth's rotation, which decreases the effect of gravity more than at any other latitude. At the poles, the centrifugal force is zero since there is no rotational velocity contributing to a centripetal effect; therefore, the effect of rotation on $ g $ is minimum (zero).</p> <p>With these considerations, the correct option is:</p> <p>Option B: Statement I is true but Statement II is false.</p>

About this question

Subject: Physics · Chapter: Gravitation · Topic: Kepler's Laws

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