v1=(2m+3m)2(m/3)0+(2m+3m)(2m−3m)v=5v
For particle A,
Initial de-Broglie wavelength
λ0=2mvh=mv2h
Final de-Broglie wavelength after collision.
λ1=2m5vh=mv10h=5λ0
Change in De-Broglie wavelength Δλ=λi−λ0=4λ0
Particle A of mass m_ A= m 2 moving along the x -axis with velocity v_0 collides elastically with another particle B at rest having mass m_ B= m 3.…
JEE Main 2020 — Physics Modern Physics
2020mcqhard
Particle A of mass mA=2m moving along the x -axis with velocity v0 collides elastically with another particle B at rest having mass mB=3m. If both the particles move along the x -axis after the collision, the change Δλ in the wavelength of the particle A, in terms of its de-Broglie wavelength (λ0) before the collision is:
Official previous-year question
Held on 4 Sept 2020 · Verified 6 Jul 2026.
Options
- A
Δλ=23λ0
- B
Δλ=25λ0
- C
Δλ=2λ0
- D
Δλ=4λ0
Did you get this right?
Sign in to track your attempts and accuracy.
Your note
Sign in to keep a private note on this question. Nothing you write is ever public.
JEE Main Modern Physics in other years
More JEE Main Modern Physics questions
An electron of mass $m$ is moving in an electric field $\vec{E} = -2E_0\hat{i}$ ($E_0 =$ constant $> 0$), with an initial velocity $\vec{V} = v_0\hat{i}$ ($v_0 =$ constant $> 0$). If $\lambda_0 = \dfrac{h}{4mv_0}$, its de Broglie wavelength at time $t$ is __________. ($e =$ charge of electron)
2026medium
In a semiconductor p-n diode, the doping concentrations on p-side and n-side are $10^{15}\text{ atoms/cm}^3$ and $10^{18}\text{ atoms/cm}^3$, respectively. Which one of the following statements is true ?
2026easy
The following diagram shows a Zener diode as a voltage regulator. The Zener diode is rated at $V_{z}=5 \mathrm{~V}$ and the desired current in load is 5 mA. The unregulated voltage source can supply upto 25 V. Considering the Zener diode can withstand four times of the load current, the value of resistor $R_{S}$ (shown in circuit) should be $\_\_\_\_$ $\Omega$. 
2026medium
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The electromagnetic wave exerts pressure on the surface on which they are allowed to fall. Reason (R): There is no mass associated with the electromagnetic waves. In the light of the above statements, choose the correct answer from the options given below :
2026medium
In hydrogen atom spectrum, $(R \rightarrow$ Rydberg's constant $)$ A. the maximum wavelength of the radiation of Lyman series is $\frac{4}{3 R}$ B. the Balmer series lies in the visible region of the spectrum C. the minimum wavelength of the radiation of Paschen series is $\frac{9}{R}$ D. the minimum wavelength of Lyman series is $\frac{5}{4 R}$ Choose the correct answer from the options given below :
2026medium
Other Physics topics for JEE Main
Keep practicing Modern Physics
Work through every JEE Main Modern Physics PYQ, year by year.