During the process of Beta decay the ratio of neutron to proton:

The correct answer is Option (2) → decreases

In beta (\( \beta^- \)) decay a neutron inside the nucleus changes into a proton, emitting an electron and an antineutrino:

    \( \displaystyle n \rightarrow p + e^- + \bar{\nu} \)

So the number of neutrons \( N \) falls by 1 and the number of protons \( Z \) rises by 1, while the mass number \( A = N + Z \) stays the same.

    \( \displaystyle \frac{N}{Z} \;\rightarrow\; \frac{N-1}{Z+1} \)

The numerator falls and the denominator rises, so the neutron to proton ratio decreases. This is why neutron-rich nuclei, which lie above the stability line, undergo beta decay.

Note: This question is from the pre-rationalised NCERT book (2022-23). The topic was removed from the latest NCERT book (2026-27), and it also appears to be out of the CUET 2026 syllabus.

NCERT (Pre-rationalised edition, 2022-23):
Beta Decay – “… In beta-minus decay, a neutron transforms into a proton within the nucleus according to

    \( \displaystyle n \rightarrow p + e^{-} + \bar{\nu} \qquad (13.24) \)”