JEE Main 2020 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 4 September 2020, Shift 2, Physics Q4

Question 4 of 75 in this shift, Physics question 4 of 25.

Consider two uniform discs of the same thickness and different radii

R_1 = R

and

R_2 = \alpha R

made of the same material. If the ratio of their moments of inertia

I_1

and

I_2

, respectively, about their axes is

I_1 : I_2 = 1 : 16

then the value of

\alpha

is :

(1) $2\sqrt{2}$
(2)2Official answer
(3)4
(4) $\sqrt{2}$

Official answer

Option 2

NTA final key (Sep 2020).

Chapter: System of Particles and Rotational Motion
Topic: Moment of Inertia
Idea tested: Scaling Laws for MOI

Same topic in other shifts

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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.