For the given reaction, the particle X is : ¹¹₆C → ¹¹₅B + β⁺ + X

75 2000 AIPMT NucleiBeta Plus Decay Easy
For the given reaction, the particle X is : ${}^{11}_{6}C \rightarrow {}^{11}_{5}B + \beta^+ + X$
A Neutron
B Anti neutrino
C Neutrino
D Proton

Detailed Solution

In $\beta^+$ decay, a proton in the nucleus changes into a neutron, emitting a positron and a neutrino: $p \rightarrow n + e^+ + \nu$.
Mass number (11) and charge ($6 = 5 + 1$) are already balanced by B and $\beta^+$, so X has zero mass number and zero charge.
Lepton number conservation requires a neutrino ($\nu$) with the positron (an antineutrino accompanies $\beta^-$ decay).
So X is a neutrino.

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