Im a uni student and a Phd student asked me in an alpha decay,(adsbygoogle = window.adsbygoogle || []).push({});

the helium nuclei is bounded by the strong nuclear force, how do the alpha particle overcome such a strong force and shoot out? And he told me it is because of quantum tunnelling.

To my understanding quantum tunnelling is an effect that due to Heisenberg's Uncertainty principle, a particle can have a distribution of energy, which there is a very low but finite probability that a particle can have enough energy to go over the energy barrier.

But I then don't understand why only certain isotopes of an element is radioactive since for those stable elements, quantum tunnelling will still take place. Someone could explain to me:D? Thanks!

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Quantum tunnelling/alpha decay

**Physics Forums | Science Articles, Homework Help, Discussion**