Physics · Gravitation

JEE Main 2026 — 5 April, Morning Shift — Question 3

When one moves from a point 16 km below the earth's surface to a point 16 km above the earth's surface. The change in g is approximately $\alpha$ %. The value of $\alpha$ is _______. (Take radius of the earth = 6400 km.)

Option A:
0.12
Option B:
0.25
Correct
Option C:
0.5
Option D:
0.75

Answer: B

Step-by-step solution

$g_{\text{above}} = g(1 - 2h/R)$ , $g_{\text{below}} = g(1 - h/R)$ . Change = $g_{\text{above}} - g_{\text{below}} = -2gh/R + gh/R = -gh/R$ . Fractional change = $h/R = 16/6400 = 0.0025 = 0.25\%$ .

Answer key and solution verified before publishing.

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Exam: JEE Main 2026
Paper: 5 April, Morning Shift
Subject: Physics
Chapter: Gravitation
Topic: Gravitational Field and Gravity