what is beta decay in radioactivity?
The radioactive decay in which high energy electrons are emitted from the nucleus of a radioactive atom is called beta decay. When a nucleus undergoes beta decay it transforms into a new nucleus after emitting a beta particle.
Example:
15P32 ---> 16S32 + -1e0
-1e0 is the beta particle of nuclear origin.
Note that in beta decay the atomic number of the new nucleus is more than the original nucleus but there is no change in mass number.