JEE Main 2020 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 3 September 2020, Shift 2, Physics Q18

Question 18 of 75 in this shift, Physics question 18 of 25.

The radius R of a nucleus of mass number A can be estimated by the formula

R = (1.3 \times 10^{-15})A^{1/3}

m. It follows that the mass density of a nucleus is of the order of : (

M_{\mathrm{prot.}} \cong M_{\mathrm{neut.}} \simeq 1.67 \times 10^{-27}

kg)

(1) $10^{3}$ kg m $^{-3}$
(2) $10^{10}$ kg m $^{-3}$
(3) $10^{17}$ kg m $^{-3}$ Official answer
(4) $10^{24}$ kg m $^{-3}$

Official answer

Option 3

NTA final key (Sep 2020).

Chapter: Nuclei
Topic: Nuclear Binding Energy
Idea tested: Nuclear Radius and Density

Same idea in other shifts

Asked 10× in all

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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.