${ }_{90}^{232} \text{Th}$ emits $6 \alpha$ and $4 \beta$ particles and gets converted into lead. The mass number and atomic number of lead is $......$

$A$ nucleus $_Z{X^A}$ emits $3 \alpha$-particles and $5 \beta$-particles. The ratio of total neutrons to protons in the final nucleus is:

Consider the following radioactive decay process:
${ }_{84}^{218} A \stackrel{\alpha}{\longrightarrow} A_1 \stackrel{\beta^{-}}{\longrightarrow} A_2 \stackrel{\gamma}{\longrightarrow} A_3 \stackrel{\alpha}{\longrightarrow} A_4 \stackrel{\beta^{+}}{\longrightarrow} A_5 \stackrel{\gamma}{\longrightarrow} A_6$
The mass number and the atomic number of $A_6$ are given by:

An artificial radioactive decay series begins with unstable $_{94}^{241}Pu$. The stable nuclide obtained after eight $\alpha$-decays and five $\beta$-decays is

In the emission of $\gamma$-rays from a nucleus:

Radioactivity was discovered by