### Theory:

Sometimes the product nucleus can be radioactive in nature and undergoes further disintegration by emitting particles like neutrons and protons. In $$1934$$, Irene Curie and F. Joliot discovered the process of artificial radioactivity.

F. Joliot and Irene Curie
Illustration of the bombardment of aluminium by $$α$$-particle:
The atoms of stable aluminium were bombarded by $$α$$-particles to produce an unstable isotope of phosphorous ($$_{15}P^{30}$$). The radioactive phosphorous gets disintegrate and produce stable silicon ($$_{14}Si^{30}$$) along with a particle having the mass same as that of an electron, but with a positive charge known as the positron. It was Carl Anderson who discovered the positive particle in the year $$1932$$.
Artificial radioactivity of aluminium by $$α$$-particle