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Friday, 9 October

JEE Main 2017 · PhysicsMultiple choiceSingle correctMediumMulti-step

JEE Main 2 April 2017 (offline), Physics Q24

Question 24 of 90 in this shift, Physics question 24 of 30.

A particle A of mass m and initial velocity vv collides with a particle B of mass m2\frac{m}{2} which is at rest. The collision is head on, and elastic. The ratio of the de-Broglie wavelengths λA\lambda_A to λB\lambda_B after the collision is :
  1. (1)λAλB=13\frac{\lambda_A}{\lambda_B}=\frac{1}{3}
  2. (2)λAλB=2\frac{\lambda_A}{\lambda_B}=2Official answer
  3. (3)λAλB=23\frac{\lambda_A}{\lambda_B}=\frac{2}{3}
  4. (4)λAλB=12\frac{\lambda_A}{\lambda_B}=\frac{1}{2}

Official answer

Option 2

CBSE answer key (25/04/2017, used for result).

Chapter
Dual Nature of Radiation and Matter
Topic
Matter Waves
Idea tested
Wavelength After Elastic Collision

Same topic in other shifts

All Matter Waves questions
  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. 5 Apr 2026, Shift 1 · Q35An electron of mass mm is moving in an electric field E⃗=−2E0i^\vec{E} = -2E_0\hat{i} (E0E_0 = constant >0> 0), with an initial velocity…MediumSingle correct
  3. 5 Apr 2026, Shift 2 · Q43An electron is travelling with a velocity vv in free space and when it enters a medium, its velocity is reduced by 20%. The de Broglie…EasySingle correct
  4. 6 Apr 2026, Shift 2 · Q47The de Broglie wavelength for an electron accelerated through the potential difference of V1V_1 volt is λ1\lambda_1. When the potential…EasyNumerical value
  5. 2 Apr 2025, Shift 2 · Q33An electron with mass mm with an initial velocity (t=0)(t=0) v⃗=v0i^\vec{v} = v_0\hat{i} (v0>0)(v_0 > 0) enters a magnetic field…MediumSingle correct
  6. 7 Apr 2025, Shift 2 · Q43A photoemissive substance is illuminated with a radiation of wavelength λi\lambda_i so that it releases electrons with de-Broglie…MediumSingle correct

Question text from the official JEE Main paper published by NTA (CBSE ran the 2017 exam); 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.