JEE Main 2022 — Physics Modern Physics

2022mcqeasy

A proton, a neutron, an electron and an $\alpha$ -particle have same energy. If ${\lambda }_{p},{\lambda }_{n},{\lambda }_{e}$ and ${\lambda }_{\alpha }$ are the de Broglie's wavelengths of proton, neutron, electron and $\alpha$ particle respectively, then choose the correct relation from the following

Official previous-year question

Held on 25 Jun 2022 · Verified 6 Jul 2026.

Options

A
${\lambda }_{p}={\lambda }_{n}>{\lambda }_{e}>{\lambda }_{\alpha }$
B
${\lambda }_{a}<{\lambda }_{n}<{\lambda }_{p}<{\lambda }_{e}$
C
${\lambda }_{e}<{\lambda }_{p}={\lambda }_{n}>{\lambda }_{\alpha }$
D
${\lambda }_{e}={\lambda }_{p}={\lambda }_{n}={\lambda }_{\alpha }$ .

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Solution

The de-Broglie wavelength $\lambda =\frac{h}{\sqrt{2m(K.E.)}}$

where, $h$ and $K.E.$ are constant

$\lambda \propto \frac{1}{\sqrt{m}}$

$m=$ Mass of the particle

Thus, with increasing mass of particle de-Broglie wavelength decreases.

Order of mass ${m}_{e}<{m}_{p}<{m}_{n}<{m}_{\alpha }$

Order of de-Broglie wavelength is ${\lambda }_{a}<{\lambda }_{n}<{\lambda }_{p}<{\lambda }_{e}$

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Options

${\lambda }_{p}={\lambda }_{n}>{\lambda }_{e}>{\lambda }_{\alpha }$

${\lambda }_{a}<{\lambda }_{n}<{\lambda }_{p}<{\lambda }_{e}$

${\lambda }_{e}<{\lambda }_{p}={\lambda }_{n}>{\lambda }_{\alpha }$

${\lambda }_{e}={\lambda }_{p}={\lambda }_{n}={\lambda }_{\alpha }$ .

Solution

The de-Broglie wavelength $\lambda =\frac{h}{\sqrt{2m(K.E.)}}$

where, $h$ and $K.E.$ are constant

$\lambda \propto \frac{1}{\sqrt{m}}$

$m=$ Mass of the particle

Thus, with increasing mass of particle de-Broglie wavelength decreases.

Order of mass ${m}_{e}<{m}_{p}<{m}_{n}<{m}_{\alpha }$

Order of de-Broglie wavelength is ${\lambda }_{a}<{\lambda }_{n}<{\lambda }_{p}<{\lambda }_{e}$

JEE Main 2022 — Physics Modern Physics

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JEE Main 2022 — Physics Modern Physics

Options

Did you get this right?

Solution

Your note

JEE Main Modern Physics in other years

More JEE Main Modern Physics questions

Other Physics topics for JEE Main

Mechanics

Electromagnetism

Optics

Thermodynamics

Waves & Oscillations

Keep practicing Modern Physics