Radioactivity is a/an ...... process.

Which of the following can penetrate through an aluminum sheet of $20 \, cm$ thickness?

$A$ nucleus $_n{X^m}$ emits one $\alpha$ and one $\beta$ particle. The resulting nucleus is:

$A$ radioactive substance emits

In a radioactive decay process,the atomic number and mass number of the nucleus do not change. Which of the following is emitted during this process?

$A$ radioactive element $A$ decays into radioactive element $C$ by the following processes in succession.
$A \rightarrow B + {}_{2}^{4}He$
$B \rightarrow C + 2e^{-}$
Then elements