The equation $\lambda=\frac{1.227}{\mathrm{x}} \mathrm{nm}$ can be used to find the de-Brogli wavelength of an electron. In this equation x stands for : Where, $\mathrm{m}=$ mass of electron $\mathrm{P}=$ momentum of electron K=Kinetic energy of electron $\mathrm{V}=$ Accelerating potential in volts for electron

JEE Main · 2022 · 28 Jul 2022 · Shift 1 · Modern Physics

The equation

λ = \frac{1.227}{x} nm

can be used to find the de-Brogli wavelength of an electron. In this equation x stands for :

Where,

m =

mass of electron

P =

momentum of electron
K=Kinetic energy of electron

V =

Accelerating potential in volts for electron

(A) $mK$
(B) $P$
(C) $K$
(D) $V$ ✓ Correct

Answer: (D)

Solution

The de Broglie wavelength is

λ = \frac{h}{2 m q V}

, where

m

is electron mass,

q

is electron charge, and

V

is accelerating potential. Substituting standard values gives

λ = \frac{1.227}{V}

nm. Therefore,

x = V

JEE Main · 2022 · 28 Jul 2022 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on Modern Physics →

More JEE Main questions on Modern Physics

7.9 MeV α-particle scatters from a target material of atomic number 79. From the given data the estimated diameter of nuclei of the target material is (approximately) ______ m.
[ $\frac{1}{4 π ϵ _{0}} = 9 \times 1 0^{9}$ Nm²/C² and electron charge $= 1.6 \times 1 0^{- 19}$ C]
JEE Main 2026View solution →
The minimum frequency of photon required to break a particle of mass 15.348 amu into $4 α$ particles is ______ kHz.
[mass of He nucleus = 4.002 amu, $1$ amu $= 1.66 \times 1 0^{- 27}$ kg, $h = 6.6 \times 1 0^{- 34}$ J.s and $c = 3 \times 1 0^{8}$ m/s]
JEE Main 2026View solution →
The smallest wavelength of Lyman series is 91 nm. The difference between the largest wavelengths of Paschen and Balmer series is nearly $____$ nm.
JEE Main 2026View solution →
Light is incident on a metallic plate having work function $110 \times 1 0^{- 20} J$ . If the produced photoelectrons have zero kinetic energy then the angular frequency of the incident light is ______ $rad / s$ . ( …
JEE Main 2026View solution →
The energy of an electron in an orbit of the Bohr's atom is $- 0.04 E_{0} eV$ where $E_{0}$ is the ground state energy. If L is the angular momentum of the electron in this orbit and h is the Planck's constant, then …
JEE Main 2026View solution →
A particle having electric charge $3 \times 1 0^{- 19} C$ and mass $6 \times 1 0^{- 27} kg$ is accelerated by applying an electric potential of 1.21 V . Wavelength of the matter wave associated with the particle is $α \times 1 0^{- 12} m$ . The va …
JEE Main 2026View solution →