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Saturday, 10 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 16 March 2021, Shift 2, Physics Q2

Question 2 of 90 in this shift, Physics question 2 of 30, Section A.

The de-Broglie wavelength associated with an electron and a proton were calculated by accelerating them through same potential of 100 V. What should nearly be the ratio of their wavelengths ? (mp=1.00727 u\mathrm{m_p}=1.00727\,u, me=0.00055 u\mathrm{m_e}=0.00055\,u)
  1. (1)43:143:1Official answer
  2. (2)1860:11860:1
  3. (3)41.4:141.4:1
  4. (4)(1860)2:1(1860)^2:1

Official answer

Option 1

NTA final key.

Chapter
Dual Nature of Radiation and Matter
Topic
Matter Waves
Idea tested
Wavelength Ratios of Different Particles

Same idea in other shifts

Asked 3× in all
  1. 4 Apr 2026, Shift 2 · Q44The de Broglie wavelength associated with an electron accelerated through a potential difference V is λe\lambda_e and the de Broglie…EasySingle correct
  2. 18 Mar 2021, Shift 1 · Q8A particle is travelling 4 times as fast as an electron. Assuming the ratio of de-Broglie wavelength of a particle to that of electron is…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 42 of the 174 JEE Main shifts held from 2017 to 2026.