JEE Main 2020 · ChemistryMultiple choiceSingle correctEasyCalculation

JEE Main 8 January 2020, Shift 2, Chemistry Q29

Question 29 of 75 in this shift, Chemistry question 4 of 25, Section A.

The radius of the second Bohr orbit, in terms of the Bohr radius,

\mathrm{a_0}

, in

\mathrm{Li^{2+}}

is :

(1) $\frac{2\mathrm{a_0}}{3}$
(2) $\frac{4\mathrm{a_0}}{3}$ Official answer
(3) $\frac{2\mathrm{a_0}}{9}$
(4) $\frac{4\mathrm{a_0}}{9}$

Official answer

Option 2

NTA final key (Jan 2020).

Chapter: Structure of Atom
Topic: Bohr's Atomic Theory
Idea tested: Bohr Radius Calculation

Same idea in other shifts

Asked 8× 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.