The $\beta$-decay of $_{11}Na^{24}$ produces an isotope of

The substance used in cancer therapy is

After the emission of a $\beta$-particle followed by an $\alpha$-particle from ${ }_{83}^{214} Bi$, the number of neutrons in the resulting atom is:

The number of $\alpha$ and $\beta$-particles emitted in the nuclear reaction $_{92}U^{238} \to _{90}Th^{234} \to _{91}Pa^{234}$ are respectively:

Which of the following has the maximum penetrating power?

Which of the following statements is not true for radioactive decay?