Learn

Saturday, 31 October

JEE Main 2026 · PhysicsMultiple choiceSingle correctMediumMulti-step

JEE Main 4 April 2026, Shift 1, Physics Q30

Question 30 of 75 in this shift, Physics question 5 of 25, Section A.

A solid sphere of mass MM and radius RR is divided into two unequal parts. The smaller part having mass M/8M/8 is converted into a sphere of radius rr and the larger part is converted into a circular disc of thickness tt and radius 2R2R. If I1I_1 is moment of inertia of a sphere having radius rr about an axis through its centre and I2I_2 is the moment of inertia of a disc about its diameter, the ratio of their moment of inertia I2/I1=I_2/I_1= ______.
  1. (1)3535
  2. (2)7070Official answer
  3. (3)140140
  4. (4)210210

Official answer

Option 2

NTA final key.

Chapter
System of Particles and Rotational Motion
Topic
Moment of Inertia
Idea tested
MOI Changes During Reshaping

Same idea in other shifts

Asked 2× in all
  1. 29 Jun 2022, Shift 2 · Q57The moment of inertia of a uniform thin rod about a perpendicular axis passing through one end is I1I_1 . The same rod is bent into a ring…MediumNumerical value

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.