JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyApplication

JEE Main 24 February 2021, Shift 2, Physics Q16

Question 16 of 90 in this shift, Physics question 16 of 30, Section A.

The de Broglie wavelength of a proton and

\alpha

-particle are equal. The ratio of their velocities is :

(1) $4:1$ Official answer
(2) $4:2$
(3) $4:3$
(4) $1:4$

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 15× in all

4 Apr 2026, Shift 2 · Q44The de Broglie wavelength associated with an electron accelerated through a potential difference V is $\lambda_e$ and the de Broglie…EasySingle correct
8 Apr 2024, Shift 2 · Q46A proton and an electron have the same de Broglie wavelength. If $K_p$ and $K_e$ be the kinetic energies of proton and electron…EasySingle correct
1 Feb 2024, Shift 1 · Q46The de Broglie wavelengths of a proton and an $\alpha$ particle are $\lambda$ and $2\lambda$ respectively. The ratio of the velocities of…EasySingle correct
11 Apr 2023, Shift 2 · Q45The ratio of the de-Broglie wavelengths of proton and electron having same Kinetic energy : (Assume $\mathrm{m_p = m_e\times1849}$ )EasySingle correct
25 Jul 2022, Shift 2 · Q37The ratio of wavelengths of proton and deuteron accelerated by potential $\mathrm{V_p}$ and $\mathrm{V_d}$ is $1:\sqrt{2}$ . Then, the…EasySingle correct
25 Jun 2022, Shift 2 · Q46A proton, a neutron, an electron and an $\alpha$ -particle have same energy. If $\lambda_p, \lambda_n, \lambda_e$ and $\lambda_\alpha$ are…MediumSingle correct
27 Jun 2022, Shift 1 · Q43An $\alpha$ particle and a carbon 12 atom has same kinetic energy K. The ratio of their de-Broglie wavelengths…EasySingle correct
31 Aug 2021, Shift 1 · Q4A moving proton and electron have the same de-Broglie wavelength. If K and P denote the K.E. and momentum respectively. Then choose the…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.