Variation of g — NEET Importance

NEET Importance Analysis

The topic 'Variation of g' is of significant importance for the NEET UG Physics section. It frequently appears in the form of multiple-choice questions, testing both conceptual understanding and numerical problem-solving skills.

Typically, 1-2 questions related to gravitation, and specifically 'g' variation, can be expected in the exam, carrying a weightage of 4-8 marks. Questions often revolve around comparing the value of 'g' at different altitudes, depths, or latitudes.

Numerical problems require the application of specific formulas for altitude ($g_h = g(1 + h/R)^{-2}$ or its approximation $g_h approx g(1 - 2h/R)$), depth ($g_d = g(1 - d/R)$), and latitude ($g' = g - Romega^2 cos^2lambda$).

Conceptual questions might ask about the reasons for these variations, the points where 'g' is maximum or minimum (e.g., poles vs. equator, surface vs. center), or the relative rates of change. A solid grasp of this topic ensures students can tackle these questions efficiently and accurately, contributing positively to their overall score in the gravitation chapter.

Vyyuha Exam Radar — PYQ Pattern

Analysis of previous year NEET (and AIPMT) questions on 'Variation of g' reveals consistent patterns. Questions are predominantly numerical, requiring direct application of the derived formulas. The most frequently tested variations are those with altitude and depth.

Often, students are asked to calculate the height or depth at which 'g' becomes a certain fraction of its surface value (e.g., $g/2$, $g/4$). Questions involving the approximate formula for altitude ($g_h approx g(1 - 2h/R)$) are common for small heights, testing the student's ability to identify when the approximation is appropriate.

The variation due to Earth's rotation is slightly less frequent but appears as conceptual questions, particularly concerning the values of 'g' at the poles and equator, or the effect of changes in Earth's angular velocity.

Comparative questions, asking to compare the decrease in 'g' for a given height versus a given depth, are also a recurring theme. The difficulty level typically ranges from easy to medium, making this a high-scoring topic if formulas and concepts are clear.