Question

if you free a neutron from A nucleus it will decay into three particles two of them are proton and electron what is the third particle

Answer 1

Decay of one neutron will give you proton, electron and neutrino.

NEUTRINO:
It is a particle of very small mass which is almost equal to zero and with zero charge and it was discovered by fermi in 1934. It is a unstable particle but less than positron.

Answer 2

The third particle that is emitted in neutron decay is antineutrino.

• Nucleus consists of neutrons and protons which are held together by nuclear force.
• Neutrons are stable inside the nucleus.
• Free neutrons are unstable and they have an average lifetime of 15 minutes approximately.
• We also face this problem in nuclear reactors where the neutrons can leak and decay.
• Neutron decays into proton, electron and antineutrino.
• Mass of neutron and proton are approximately same with 939.57 MeV and 938.28 MeV.
• Antineutrinos are leptons which are counterparts of neutrinos with very negligible mass.