The ratio of radii for the first and third orbits of hydrogen atom is $1 : x$. The value of $x$ is $\underline{\hspace{2em}}$. (Integer answer)

JEE Main 2021 · ChemistryNumerical answerNumerical valueEasyCalculation

JEE Main 3 August 2021, Shift 2, Chemistry Q53

Question 53 of 90 in this shift, Chemistry question 23 of 30, Section B.

The ratio of radii for the first and third orbits of hydrogen atom is

1 : x

. The value of

x

\underline{\hspace{2em}}

. (Integer answer)

Official answer

NTA final key.

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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26 Jun 2022, Shift 1 · Q63If the radius of the 3 $^{rd}$ Bohr's orbit of hydrogen atom is r $_3$ and the radius of 4 $^{th}$ Bohr's orbit is r $_4$ . Then :EasySingle correct
8 Jan 2020, Shift 2 · Q29The radius of the second Bohr orbit, in terms of the Bohr radius, $\mathrm{a_0}$ , in $\mathrm{Li^{2+}}$ is :EasySingle correct
5 Sep 2020, Shift 1 · Q41The difference between the radii of $3^{\mathrm{rd}}$ and $4^{\mathrm{th}}$ orbits of $\mathrm{Li^{2+}}$ is $\Delta R_1$ . The difference…MediumSingle correct
2 Apr 2017 (offline) · Q38The radius of the second Bohr orbit for hydrogen atom is : (Planck's Const. $h=6.6262\times10^{-34}$ Js; mass of electron…EasySingle correct

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.