Question

A free neutron decays spontaneously into a proton,an electron and $\underset{–}{}$

• A. an anti-neutrino
• B. a neutrino
• C. a neutrino and an anti-neutrino
• D. None

Answer 1

Answer: (A)

an anti-neutrino

Neutron is unstable outside the nucleus.
It's decaying equation is given below.
${}_0{n}^1{\Rightarrow }_1^{1}H{+}_{-1}^{0}e+\overline{v}$