Choose the correct nuclear process from the below options [p: proton, n: neutron, $\mathrm{e}^{-}$: electron, $\mathrm{e}^{+}$: positron, v: neutrino, $\bar{\nu}$: antineutrino]

(A) $n \rightarrow p+e^{-}+\bar{v}$

(C) $n \rightarrow p+e^{+}+\bar{v}$

JEE Main · 2025 · 28 Jan 2025 · Shift 1 · Modern Physics

Choose the correct nuclear process from the below options
[p: proton, n: neutron,

e^{-}

: electron,

e^{+}

: positron, v: neutrino,

\overset{ν}{ˉ}

: antineutrino]

(A) $n \to p + e^{-} + \overset{v}{ˉ}$ ✓ Correct
(B) $n \to p + e^{-} + v$
(C) $n \to p + e^{+} + \overset{v}{ˉ}$
(D) $n \to p + e^{+} + v$

Answer: (A)

Solution

In beta-minus decay, a free neutron converts to a proton while emitting an electron and an antineutrino:

n \to p + e^{-} + \overset{ν}{ˉ}

This conserves charge (

0 \to + 1 - 1 + 0

), baryon number (

1 \to 1 + 0 + 0

) and lepton number (

0 \to 0 + 1 - 1

); it is specifically the antineutrino, not the neutrino, that must accompany the electron for lepton number to balance.

JEE Main · 2025 · 28 Jan 2025 · 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 →