NEET UG 2025 · Physics · Question 39
NEET 2025 Physics, question 39
Question 39 of the NEET 2025 paper (code 45) is a Physics question from System of Particles and Rotational Motion. Its idea, Parallel and Perpendicular Axis Theorems, was asked twice, in 2025 and 2026, across NEET 2017–2026. The NTA final answer key gives option 3.
Updated 2026-10-08
Q39 · Physics
A sphere of radius is cut from a larger solid sphere of radius as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is :
The figure, described in words
Large sphere of radius 2R centred on origin (Y-axis through centre); small sphere of radius R cut out, touching the large sphere's surface on the +X side, its centre at distance R from the Y-axis.
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- 3Official answer
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Official answer: option 3 · NTA final answer key
Same idea
Parallel and Perpendicular Axis Theorems, in other papers
NEET asked this idea twice, in 2025 and 2026. The other question below.
- 2026 Q27A solid sphere A of radius R and mass M is attached at a point to a smaller solid sphere B of radius and mass . Assume that the…Numerical · Medium
Parallel and Perpendicular Axis Theorems: every question and how it was framed
The chapter
System of Particles and Rotational Motion in ten years of NEET
25 questions from 2017–2026, asked in 10 of 10 papers, about 2.4 a paper. Rotational Motion alone had 21.