The correct order of ionizing capacity of $\alpha, \beta,$ and $\gamma$ rays is:

In the Uranium radioactive series,the initial nucleus is ${ }_{92}^{238} U$ and the final nucleus is ${ }_{82}^{206} Pb$. When the Uranium nucleus decays to lead,the number of $\alpha$-particles emitted is .......... and the number of $\beta$-particles emitted is ..........

The number of $\alpha$ and $\beta^-$ particles emitted during the radioactive decay chain starting from ${}_{88}^{226}Ra$ and ending at ${}_{82}^{206}Pb$ is:

At a specific instant,the emission of a radioactive compound is deflected in a magnetic field. The compound can emit:
$(i)$ Electrons
$(ii)$ Protons
$(iii)$ $He^{2+}$
$(iv)$ Neutrons
The emission at that instant can be:

Who discovered radioactivity?

When $_{90}Th^{238}$ transforms into $_{83}Bi^{222}$,the number of $\alpha$ and $\beta$ particles emitted are: