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Saturday, 31 October

JEE Main · Chemistry · Structure of Atom

Bohr Radius Calculation

JEE Main asked Bohr Radius Calculation 8 times in 8 of the 108 shifts Lumi analysed, in 2017, 2020, 2021, 2022, 2025 and 2026. It belongs to Bohr's Atomic Theory, in Structure of Atom (Chemistry). The longest wait between two years asking it was 3 years, across 2018 and 2019, which Lumi has no shifts for. In 2020 and 2026 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked
8
in 8 shifts
Years
6 of 8
First asked
2017
last in 2026
Pattern
Asked most years
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2017, 2020, 2021, 2022, 2025 and 2026. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Chemistry questions.

00.510.83’170.17’200.03’210.03’220’230’240.13’250.22’26

Raw count: 2017: 1 in 1 shift · 2020: 2 in 12 shifts · 2021: 1 in 24 shifts · 2022: 1 in 24 shifts · 2023: 0 in 12 shifts · 2024: 0 in 18 shifts · 2025: 1 in 8 shifts · 2026: 2 in 9 shifts.

Shift by shift

Each square is one analysed shift, in date order. Open a filled one for that paper.

  • 20262 of 9
  • 20251 of 8
  • 20240 of 18
  • 20230 of 12
  • 20221 of 24
  • 20211 of 24
  • 20202 of 12
  • 20171 of 1

Asked in that shift More than once Not asked

How JEE Main framed it

Single correct is the usual form. Skill tested: calculation.

  • Ratio of bohr orbit radii
  • Identify species with identical bohr radii

Difficulty

Easy 7Medium 1Hard 0

1 of the 8 questions had a numerical answer.

Every question

All 8 questions

From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.

  1. 6 Apr 2026, Shift 2 · Q52The Bohr radius of a hydrogen like species is 70.53 pm. The species and the stationary state (nn) are respectively (Given : Hydrogen atom…EasySingle correct
  2. 4 Apr 2026, Shift 2 · Q52The species having identical radii according to the Bohr's theory are: A. H (first orbit) B. He+\mathrm{He^+} (first orbit) C.…EasyOther
  3. 2 Apr 2025, Shift 1 · Q52According to Bohr's model of hydrogen atom, which of the following statement is incorrect ?EasySingle correct
  4. 26 Jun 2022, Shift 1 · Q63If the radius of the 3rd^{rd} Bohr's orbit of hydrogen atom is r3_3 and the radius of 4th^{th} Bohr's orbit is r4_4. Then :EasySingle correct
  5. 3 Aug 2021, Shift 2 · Q53The ratio of radii for the first and third orbits of hydrogen atom is 1:x1 : x. The value of xx is ‾\underline{\hspace{2em}}. (Integer…EasyNumerical value
  6. 5 Sep 2020, Shift 1 · Q41The difference between the radii of 3rd3^{\mathrm{rd}} and 4th4^{\mathrm{th}} orbits of Li2+\mathrm{Li^{2+}} is ΔR1\Delta R_1. The difference…MediumSingle correct
  7. 8 Jan 2020, Shift 2 · Q29The radius of the second Bohr orbit, in terms of the Bohr radius, a0\mathrm{a_0}, in Li2+\mathrm{Li^{2+}} is :EasySingle correct
  8. 2 Apr 2017 (offline) · Q38The radius of the second Bohr orbit for hydrogen atom is : (Planck's Const. h=6.6262×10−34h=6.6262\times10^{-34} Js; mass of electron…EasySingle correct

Shifts: 2 Apr 2017 (offline), 8 Jan 2020, Shift 2, 5 Sep 2020, Shift 1, 3 Aug 2021, Shift 2, 26 Jun 2022, Shift 1, 2 Apr 2025, Shift 1, 4 Apr 2026, Shift 2, 6 Apr 2026, Shift 2.

Same topic

Other ideas in Bohr's Atomic Theory

Bohr's Atomic Theory has 14 ideas JEE Main has asked; 10 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisStudy this chapterAll repeated ideas