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Friday, 9 October

NEET UG 2026 · Physics · Question 27

NEET 2026 Physics, question 27

Question 27 of the NEET 2026 paper (re-exam) 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 2.

Updated 2026-10-08

Q27 · Physics

A solid sphere A of radius R and mass M is attached at a point to a smaller solid sphere B of radius r<Rr<R and mass m<Mm<M. Assume that the line joining their centres lies along the horizontal. The moment of inertia of the system calculated about a vertical axis passing through the centre of A is IAI_A and that calculated about a vertical axis passing through the centre of B is IBI_B. The difference IA−IBI_A-I_B is :

The figure, described in words

Stem figure: two diagrams of large sphere A and small sphere B touching, with dashed vertical axes through centre of A (I_A) and through B (I_B).

  1. 1(M−m)(R+r)2(M-m)(R+r)^2
  2. 2(m−M)(R+r)2(m-M)(R+r)^2Official answer
  3. 3(m−M)(R−r)2(m-M)(R-r)^2
  4. 40

Official answer: option 2 · 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.

  • 2025 Q39A sphere of radius RR is cut from a larger solid sphere of radius 2R2R as shown in the figure. The ratio of the moment of inertia of the…Figure-based · Hard

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.

Chapter analysisStudy this chapterPractise this chapter

System of Particles and Rotational Motion: questions per paper

0243’174’182’192’202’213’221’232’243’253’26