A nucleus of an element ${}_{84}{X^{202}}$ emits an $\alpha $-particle first, $\beta $ -particle next and then a gamma photon. The final nucleus formed has an atomic number

In the given nuclear reaction $A, B, C, D, E$ represents

$_{92}{U^{238}}{\xrightarrow{\alpha }_B}T{h^A}{\xrightarrow{\beta }_D}P{a^C}{\xrightarrow{E}_{92}}{U^{234}}$

In the disintegration series the $_{92}^{238}U\xrightarrow{\alpha }X\xrightarrow{{\beta  - }}_Z^AY$ values of $Z$ and $A$ respectively will be

Before the neutrino hypothesis, the beta decay process was thought to be the transition, $n \to p + {e^ - }$ If this was true, show that if the neutron was at rest, the proton and electron would emerge with fixed energies and calculate them. Experimentally, the electron energy was found to have a large range. 

The total number of $\alpha$ and $\beta$ particles emitted in the nuclear reaction ${ }_{92}^{238} \mathrm{U} \rightarrow{ }_{82}^{214} \mathrm{~Pb}$ is

In the disintegration series

$_{92}^{238}U\xrightarrow{\alpha }x\xrightarrow{\beta }_Z^AY$

The value of $Z$ and $A$ respectively will be